A prepositional idiom consists of a verb followed by a preposition, but unlike an ordinary prepositional phrase, it forms an expression with a nonliteral or idiomatic meaning. Some grammarians consider the prepositional idiom a type of a phrasal verb, others call it the phrasal verb itself, and still others call it a verb phrase. Anyway we call it, however, the distinguishing characteristic of a prepositional idiom is that its meaning is largely determined by the preposition that comes after the verb; in fact, a single verb can yield as many as five or many more meanings depending on the preposition that comes after it.

For example, the verb “back,” which literally means “to support by material or moral assistance” or “to cause to go back or in reverse,” yields at least nine different meanings when followed by different prepositions, as follows:

back down – cease defending one’s position in a debate or argument.
Example: He’s not the type who’ll back down from a fight because of veiled threats.

back away – get out from a previous commitment.
Example: The consortium partner backed away from the deal for undisclosed reasons.

back out – renege from a promise or deal.
Example: The boxer backed out from the title fight due to disagreements over the prize money.

back up (1) – provide support to someone or something.
Example:  The reporter was asked to back up his exposé with documentary evidence.

back up (2) – move backwards or in reverse.
Example: She backed up the car so fast that it hit the lamppost.

back out of – not keep a promise or deal.
Example:  His lawyer backed out of the case the day before the trial.

back into – hit something while moving backwards.
Example: She backed into a lamppost while getting out of the parking slot.

back off – escape or run away from something.
Example: The police told the demonstrators to back off or face dispersal.

back of – unspoken self-knowledge about the outcome of something
Example: He decided to fight, but back of his mind he knew that it was a losing battle.

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Idioms that start with in

The table below shows various examples of prepositional idioms that start with the preposition in:

Idiom	Meaning	Example Sentence
in advance	ahead of time; before	“Sue paid for her gift in advance.”
in brief	concisely; in a few words	“This textbook explains World War II in brief.”
in bulk	in large amounts	“We always buy toilet paper in bulk.”
in common	sharing a trait with someone or something else	“Dogs and wolves have several traits in common.”
in danger	prone to danger or threatened by a dangerous situation; about to be harmed	“Those little kids are in danger.”
in debt	owing money	“Many students are in debt due to the expense of higher education.”
in demand	desired; wanted; sought after (usually skills or products)	“Computer skills are really in demand these days.”
in depth	thoroughly; comprehensively	“Students must discuss their proposals in depth with their advisers.”
in detail	thoroughly; comprehensively	“Writers describe everything in detail.”
in the end	finally; at last	“In the end, what matters most is honesty.”
in fact	really; actually	“The man who is dressed in a T-shirt and jeans is in fact the CEO.”
in general	usually; most of the time	“In general, owners should feed their pets at least twice a day.”
in a minute	very soon	“Angela will arrive in a minute.”
in particular	especially	“I love history in general, but I would like to learn more about European history in particular.”
in reality	really; actually	“Oftentimes, the most talkative people are in reality quite shy.”

Idioms that start with on

The table below shows various examples of prepositional idioms that start with the preposition on:

Idiom	Meaning	Example Sentence
on average	usually; typically; normally	“Bruce works out on average four times a week.”
on board	located on a ship, train, or airplane	“The ship will depart once everyone is on board.”
on demand	immediately available when asked for or requested	“Most people prefer to watch movies on demand.”
on display	being shown, showcased, or exhibited	“A famous painting is now on display at the museum.”
on fire	in flames; burning	“A building was on fire yesterday.”
on hand	available, accessible	“Do you have a notepad on hand?”
on the other hand	in contrast (to a previously stated point of view)	“It’s fun to see movies, but on the other hand tickets can be quite expensive.”
on purpose	intentionally; deliberately	“Liz left without us on purpose.”
on sale	being sold, especially at a reduced price	“The hat you wanted is on sale at the mall.”
on schedule	functioning as planned or scheduled	“The buses seem to be on schedule today.”
on time	at the planned or expected time (e.g., of arrival)	“Alfred never arrives on time.”

Idioms that start with out of

The table below shows various examples of prepositional idioms that start with the preposition out of:

Idiom	Meaning	Example Sentence
out of the blue	without prior indication; unexpectedly	“He showed up at our house out of the blue.”
out of breath	tired; exhausted; panting	“She became out of breath after trudging up the stairs.”
out of character	contrary to one’s personality	“Teresa has been acting out of character lately.”
out of harm’s way	safe	“I’m just glad the baby is out of harm’s way.”
out of order	not functioning or working properly; temporarily broken or unusable (usually referring to machinery)	“This printer is out of order.”
out of the ordinary	unusual; not normal	“His methods are out of the ordinary.”
out of print	no longer published or printed (usually referring to books)	“Unfortunately, that book is out of print.”
out of the question	impossible or unlikely; unreasonable	“Your request is out of the question.”
out of season	not ripe or readily available (usually fruits or vegetables)	“Grapes are out of season this time of year.”
out of style	not fashionable or hip	“Perms have been out of style for decades.”
out of time	having no more (remaining) time	“We are almost out of time.”
out of town	temporarily away at a location in a different vicinity	“Brian will be out of town this weekend.”
out of work	unemployed	“Most of my friends are unfortunately out of work.”

Idioms that start with at

The table below shows various examples of prepositional idioms that start with the preposition at:

Idiom	Meaning	Example Sentence
at all times	always	“Wear your seatbelt at all times.”
at fault	responsible for something bad; culpable	“She is the only one at fault.”
at first	in the beginning; initially	“At first, she attempted to speak to everyone individually.”
at hand	near in space or time	“Always keep your passwords close at hand.”
at last	finally	“He made it to the airport at last.”
at once	immediately	“Go to your room at once!”
at rest	motionless	“An object at rest stays at rest unless acted on by an outside force.”
at risk	prone to danger or threatened by a dangerous situation	“Families residing near the volcano are especially at risk.”

Idioms that start with for

The table below shows various examples of prepositional idioms that start with the preposition for:

Idiom	Meaning	Example Sentence
for certain	surely; definitely; positively	“Is Desmond coming to the party tomorrow for certain?”
for example	as an example; for instance	“English isn’t the only international language; for example, French is the national language of many different countries.”
for fun	as a hobby; for enjoyment	“What do you usually do for fun?”
for good	permanently or for an extended period of time	“I’ve decided to leave this city for good.”
for a living	as an occupation	“Herman cleans houses for a living.”
for now	temporarily; for the time being	“Please go to the waiting room for now.”
for sale	being sold; available to be purchased	“Is this diamond ring for sale?”

Idioms that start with by

The table below shows various examples of prepositional idioms that start with the preposition by:

Idiom	Meaning	Example Sentence
by accident	unintentionally; not deliberately	“The kids broke the vase by accident.”
by all means	definitely; certainly	“Prospective students are by all means encouraged to visit the campus.”
by hand	without the use of machinery	“He makes intricate sculptures by hand.”
by mistake	unintentionally; not deliberately; as a mistake	“I went to the wrong location by mistake.”
by the way	incidentally (used to introduce a different topic)	“By the way, have you written your essay yet?”

Idioms that start with from

The table below shows various examples of prepositional idioms that start with the preposition from:

Idiom that Starts with From	Meaning	Example Sentence
from afar	from a distance; coming from far away	“I could hear music from afar.”
from head to toe	all over the body	“She was covered in mud from head to toe.”
from scratch	from the beginning and using only the basic elements or ingredients	“Bob made raspberry cupcakes from scratch.”
from time to time	occasionally; infrequently	“They return to their home country from time to time.”

Souce: https://www.thefreedictionary.com/Idioms-that-Start-with-Prepositions.htm