at the drop of a hat Definition

drop
verb dropped, dropping

tr & intr
1. To fall or allow to fall.

Thesaurus: drip, fall, dribble, trickle, leak, distill.
tr & intr
2. To decline or make something decline; to lower or weaken.
3. To give up or abandon (eg a friend or a habit); to stop doing something.

Thesaurus: forsake, part with, cast off, abandon, desert, leave, divorce, separate from.
4. To stop discussing (a topic).
5. To set them down from a vehicle; to deliver or hand them in.

Form: drop someone off (also)
Form: drop something off
6. To leave or take out someone or something.

Example: They've dropped me from the team
7. To mention something casually.

Example: drop a hint
8. To fail to pronounce (especially a consonant).

Example: drop one's h's
9. colloq
To write informally.
Example: Drop me a line
10. rugby.
To score (a goal) by a drop kick.
11. coarse slang except when said of an animal
To give birth to (a baby).
12. slang
To beat to the ground.

noun

1. A small round or pear-shaped mass of liquid, especially when falling; a small amount (of liquid).

Thesaurus: bit, speck, dab, dash, pinch, spot, shot, nip, trace, droplet.
2. A descent; a fall.
3. A vertical distance.
4. A decline or decrease.

Thesaurus: fall, tumble, reduction, decrease, descent, slump, lapse, slip, decline, downfall, declivity, precipitation.
5. Any small round or pear-shaped object, eg an earring or boiled sweet.
6. Liquid medication administered in small amounts.

Example: eye drops
Form: drops
7. A delivery.
8. Used of something that drops, or that is used in or for dropping.

Form: drop- (usually)

Idiom: at the drop of a hat

colloq
Promptly; for the slightest reason.

Idiom: let something drop

To make it known inadvertently or as if inadvertently.

Etymology: Anglo-Saxon droppian.

Phrasal Verb: drop back or behind

To get left behind others in a group.

Phrasal Verb: drop in or by

To pay a brief unexpected visit.

Phrasal Verb: drop into something

To pass idly or passively into (a habit, etc).

Phrasal Verb: drop off

To fall asleep.To become less; to diminish; to disappear.

Phrasal Verb: drop out

To withdraw from an activity.To adopt an alternative lifestyle as a reaction against traditional social values. See also dropout.

Phrasal Verb: drop out of something

To withdraw eg from a pre-arranged activity.

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hat
noun

1. A covering for the head, usually worn out of doors.
2. colloq
A role or capacity.
Example: wearing her vet's hat

verb

hatted, hatting
1. To provide someone with a hat or put a hat on someone.

Derivative: hatless
adj

Idiom: a bad hat

colloq
An unscrupulous person.

Idiom: at the drop of a hat

See under drop.

Idiom: keep something under one's hat

colloq
To keep it secret.

Idiom: my hat!

An exclamation expressing surprise or disbelief.

Idiom: old hat

colloq
So well known, familiar, etc as to be tedious and uninteresting.

Idiom: pass the hat round (send the hat round)

To collect money for a cause.

Idiom: take one's hat off to someone

colloq
To admire or praise them, especially for some particular achievement.

Idiom: talk through one's hat

To talk nonsense.

To deceive or bluff.

Idiom: throw one's hat into the ring

See under ring¹.

Idiom: wear several hats (wear another hat)

To act in several roles or capacities.

Etymology: Anglo-Saxon hæt.