At the drop of a hat:

"without needing any advance notice"
My Grandma will babysit for anyone at the drop of a hat.

(have a) bee in one's bonnet:

"something that is annoying someone"
Milan has had a bee in his bonnet all day, but he won't tell me what's wrong.

below the belt:

"beyond what is fair or socially acceptable"
His comment about Manfred's handicap was below the belt.

bursting at the seams:

"not fitting anymore"
I ate too much. I'm bursting at the seams in these jeans.

caught with one's pants down:

"unprepared"
My students caught me with my pants down on Monday. I forgot about the field trip.

(have a) card up one's sleeve:

"have a secret or reserve plan"
I think Josh has a card up his sleeve cause he wants me to wear a dress to the fast-food restaurant.

buckle down:

"work extra hard"
It's almost exam time, so I need to buckle down this weekend.

burn a hole in one's pocket:

"money that one is tempted to spend"
Let's go to the mall after school. There's a hundred dollar bill burning a hole in my pocket.

dress to kill, dress to the nines:

"dress in nice clothes"
My cousin was dressed to kill on her birthday.

fit like a glove:

"fit perfectly (tight to one's body)"
Anita's prom dress fits me like a glove.

fine-tooth comb:

"in great detail, extremely carefully"
The police looked for fingerprints with a fine-tooth comb.

fly by the seat of one's pants:

"do by instinct, not by plan"
I had never taught art to kids before. I had to fly by the seat of my pants.

handle with kid gloves:

"treat delicately"
Please handle my grandmother's tea set with kid gloves.

hand-me-down:

"used clothing"
We buy hand-me-down skates because the kids' feet grow so quickly.

hat trick:

"three goals scored by one person"
The fans cheered when the hockey player got a hat trick.


keep one's shirt on:

"try to stay calm"
I know you're in a hurry, but please keep your shirt on.

keep something zipped:

"keep something a secret"
We know we're having a surprise party, but we're keeping it zipped from the grandparents.

off the cuff:

"said without planning"
I didn't have a speech prepared. Everything I said was off the cuff.

pull up one's socks:

"try harder"
Marco will have to pull up his socks if he wants to make the football team.

put a sock in it:

"stop talking"
Put a sock in it! I'm trying to tell a story.

put one's thinking cap on:

"think hard in order to solve a problem"
I can't remember where the Christmas decorations are. I'll have to put my thinking cap on.

put oneself in someone else's shoes:

"imagine what it would be like to be in someone else's situation"
Put yourself in Amber's shoes. She doesn't even have a car to drive.

ride one's coattails:

"let someone else do all of the work"
It was a group project, but everyone rode Andrew's coattails.

roll up one's sleeves:

"get down to hard work"
The celebrities rolled up their sleeves and washed cars for charity.

take one's hat off to someone:

"recognize or honor someone for something"
I take my hat off to Jim. The doctors said he'd never walk, and he just ran a marathon.

wear one's heart on one's sleeve:

"display emotions openly"
My Dad's not afraid to cry. He always wears his heart on his sleeve.

wear the trousers:

"be in charge, make the rules"
By the looks of things, the kids wear the trousers in this household.