Merriam-Webster Logo
SINCE 1828
Menu
×

An Encyclopædia Britannica Company

See What's Trending Now See More Trending Words
1

ad-lib

play
verb \ ˈad-ˈlib \

Definition of ad-lib

ad-libbed; ad-libbing
transitive verb
:to deliver spontaneously
intransitive verb
:to improvise especially lines or a speech
—

ad-lib

noun

See ad-lib defined for English-language learners

See ad-lib defined for kids

From the M-W Editors

alt-59c52d6ee2f72
Breathing Life Into 'Inspire'
young-plant-shoots
Merriam-Webster's New Words Quiz—Fall 2017 Edition!
video-title-words-of-the-year-1066
Words of the Year: 1066
image1644821030
These Are Fighting Words

Origin and Etymology of ad-lib

ad lib

ad-lib Synonyms

Synonyms
ad-lib, clap (together or up), extemporize, fake
Related Words
concoct, contrive, cook (up), devise, fabricate, hatch, invent, make up, manufacture, think (up); cobble (together or up), dash (off)
Near Antonyms
arrange, lay, prepare, ready; consider, contemplate, ponder, study; exercise, practice (also practise), rehearse
2

ad-lib

adjective

Definition of ad-lib

:spoken, composed, or performed without preparation

First Known Use of ad-lib

1819

ad-lib Synonyms

Synonyms
ad hoc, ad-lib, down and dirty, extemporary, extempore, impromptu, improvisational, improvised, offhand, offhanded, off-the-cuff, snap, spur-of-the-moment, unconsidered, unplanned, unpremeditated, unprepared, unrehearsed, unstudied
Antonyms
considered, planned, premeditated, premeditative, prepared, rehearsed
Related Words
unscripted; automatic, impulsive, instinctive, involuntary, spontaneous; casual, cursive, informal, unauthorized; half-baked, half-cocked, ill-advised
Near Antonyms
deliberate, intended, intentional

ad lib

adverb

Definition of ad lib

1 :in accordance with one's wishes
2 :without restraint or limit

See ad lib defined for kids

Origin and Etymology of ad lib

New Latin ad libitum

AD-LIB Defined for English Language Learners

ad-lib

play
verb

Definition of ad-lib for English Language Learners

  • : to make up words or music in a performance instead of saying or playing something that has been planned

AD-LIB Defined for Kids

ad-lib

verb \ ˈad-ˈlib \

Definition of ad-lib for Students

ad-libbed; ad-libbing
:to make up something and especially music or spoken lines during a performance :improvise

Medical Dictionary

ad-lib

adjective \ (ˈ)ad-ˈlib \

medical Definition of ad-lib

:made or done spontaneously :not controlled by a schedule
  • ad-lib feeding of animals

ad lib

play
adverb \ (ˈ)ad-ˈlib \

medical Definition of ad lib

:without restraint or imposed limit :as much or as often as is wanted
  • the animals were given water ad lib
  • —Science
—often used in writing prescriptions

Learn More about ad-lib

  1. See words that rhyme with ad-lib Thesaurus: All synonyms and antonyms for ad-lib Nglish: Translation of ad-lib for Spanish speakers

Seen and Heard

What made you want to look up ad-lib? Please tell us where you read or heard it (including the quote, if possible).

show hide

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

toothsome

play

agreeable, attractive, or delicious

Get Word of the Day daily email!

TRENDING NOW

  1. dotage, dotard a state or period of senile decay

  2. otherwise "in other respects"

  3. federalism Graham says bill gives power to states

  4. bodega "Don’t mess with the beloved bodega."

  5. carceral Of, relating to, or suggesting a jail or prison

SEE ALL

BROWSE DICTIONARY

ad-lib

Test Your Vocabulary

Merriam-Webster's New Words Quiz—Fall 2017 Edition!

  • young-plant-shoots
  • Which of the following is a new sense of the word bunny?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Add Diction

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

alt-59c52d6ee2f72
Breathing Life Into 'Inspire'

The word's origins are quite literal

alt-59c4207ecf106
Let's Talk 'Tea'

Spill it, sip it: just make it hot.

image1644821030
8 Words and Phrases from Boxing and Wrestling

Common terms that come from boxing and wrestling

alt-59c2960017c94
The Ambiguity of Pushing 'Up' and 'Back'

When you push a meeting, where does it go?

Ask the Editors

video-title-words-of-the-year-1066
Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

payday
How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless
Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals
Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

young-plant-shoots
Merriam-Webster's New Words Quiz—Fall 2017 Edition!

You're going to have to memorize the dictionary again.

Take the quiz
stylized-drawing-of-woman-pole-vaulting-across-gap-to-get-trophy
Challenging Vocabulary Quiz Returns!

No tricks, just difficult words.

Take the quiz
True or False
True or False?

Test your knowledge - and maybe learn something along the way.

Take the quiz
Add Diction
Add Diction

Build a chain of words by adding one letter at a time.

Play the game