Idioms in alphabetical order

Here're 51 idioms starting with O.
A B C D E F G H I J K L M N O P R S T U W Y

ODD MAN OUT
the person who is left out; the person who doesn’t fit in
ODDS AND ENDS
small items that are left over, don’t match, or are missing a mate
OFF (ONE'S) ROCKER
out of one’s mind; slightly crazy
OFF THE BEATEN PATH/TRACK
off the road or way that is most often chosen by other people
OFF THE CUFF
without much advance preparation; spontaneously
OFF THE TOP OF (ONE'S) HEAD
to say smth. without much advance preparation
OFF THE WALL
unusual; peculiar
OLD FLAME
someone from a past romantic relationship
OLD FUDDY-DUDDY
a person who is old-fashioned and not open to new technology or ideas
OLD HAT
routine to the point of boredom (1); old-fashioned and outmoded (2)
OLD-BOY NETWORK
the male connections that a man acquires, usually while in college or the military, later used to disseminate jobs and information
ON (ONE'S) LAST LEGS
about to die, fail, or collapse
ON (THE) CLOUD NINE
blissfully happy
ON A/THE WARPATH/RAMPAGE
looking for a fight; very angry and upset with someone or smth.
ON FIRE
in a state of ignition (1); feeling very hot and painful (2); playing, working, etc. extremely well (opt. 3)
ON HOLD, PUT (SMTH.)
to postpone smth.; to wait until later (1&2); to ask somebody to wait without hanging up the telephone
ON ICE, PUT (SMTH.)
to put smth. (an excess of some item) in reserve for later use
ON PINS AND NEEDLES
worried or excited about smth. that is going to happen
ON STEROIDS
to say that smth. is an extreme example or version of smth.
ON THE BACK BURNER, PUT (SMTH.)
to decrease the amount of energy spent on some activity; to delay or postpone action on some activity
ON THE BALL
mentally sharp or alert; well-prepared; efficient
ON THE BLINK
not working correctly
ON THE FRITZ
not working correctly
ON THE GO
constantly busy; very active
ON THE LEVEL
honest and without deception
ON THE ROCKS
unstable; likely to collapse. When referring to alcoholic beverages, it means with ice cubes
ON THE SAME PAGE
working in harmony; to be thinking in a similar fashion
ON THE TIP OF (ONE'S) TONGUE
almost remembered; about to be said
ON THE UP AND UP
honest; ethical; fair
ON THE WAGON
to abstain from drinking alcoholic beverages because one cannot control oneself
ON THIN ICE, SKATE/TREAD
in an unsafe or risky position
ON/OFF A/THE TREADMILL
in a dull and boring routine
ONCE IN A BLUE MOON
very rarely
ONE FELL SWOOP
one quick, sweeping action
ONE'S LIPS ARE SEALED
to keep a secret
ONE'S NEAREST AND DEAREST
close relatives and friends
OPEN BOOK
a person who doesn’t hide anything about himself or herself; a person’s life or mind in which nothing is hidden
OPEN MIND, (KEEP) AN
to be willing to listen to and consider all sides of an issue; not to have made up one’s mind in advance
OPEN-MINDED
willing to consider new ideas
OUT OF A CLEAR BLUE SKY
without warning
OUT OF CIRCULATION
removed from the public; no longer available for use or social interaction
OUT OF ONE'S DEPTH/LEAGUE
beyond one’s capability
OUT OF THE BLUE
suddenly and unexpectedly
OUT OF THE FRYING PAN AND INTO THE FIRE
from a bad situation to one that is even worse
OUT OF THE WOODS
out of danger; out of a very difficult situation
OUT OF THIS WORLD
extremely good or impressive (1); beyond ordinary or usual (2)
OUT TO LUNCH
absent-minded, unaware or confused (1); ignorant on some topic (2); harmlessly crazy or out of touch with reality
OVER A BARREL
in a difficult situation or position
OVER ONE'S HEAD
too difficult or strange for you to understand
OVER THE HILL
too old to be of much value
OVER THE TOP
beyond expectations; outside normal or accepted boundaries; exaggerated

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