ad lib

¹ American  

[ad lib, ad] / æd ˈlɪb, ˈæd /

noun

1. something improvised in speech, music, etc..

   Was that joke part of your speech or an ad lib?

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adverb

1. at one's pleasure; without restriction.

2. freely; as needed; without stint.

   Water can be given to the patients ad lib.

ad lib. ² American  

abbreviation

1. ad libitum.

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ad-lib ³ American  

[ad-lib, ad-] / ædˈlɪb, ˈæd- /

verb (used with object)

ad-libbed, ad-libbing

1. to improvise all or part of (a speech, a piece of music, etc.).

   to ad-lib one's lines.

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verb (used without object)

ad-libbed, ad-libbing

1. to act, speak, etc., without preparation.

   Throughout the play he had to ad-lib constantly.

adjective

1. impromptu; extemporaneous.

   ad-lib remarks to hecklers.

ad-lib British  

/ ædˈlɪb /

verb

1. to improvise and deliver without preparation (a speech, musical performance, etc)

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adjective

1. improvised; impromptu

adverb

1. without restraint; freely

2. music short for ad libitum

noun

1. an improvised performance, often humorous

Other Word Forms

• ad-libber noun

Etymology

Origin of ad lib¹

First recorded in 1810–20; ad libitum

Origin of ad-lib³

1915–20, v. use of ad lib

Example Sentences

It was almost like a comedy ad lib session.

From Los Angeles Times • Dec. 14, 2023

Sure enough, after three months, the mice who ate ad lib were stricken with obesity, diabetes, liver disease, and a host of other ugly conditions.

From Salon • Oct. 9, 2022

There are conflicting stories about when the ad lib started.

From Seattle Times • Jan. 19, 2021

But then he remembered he was meant to keep going for at least 35 minutes, so he began to ad lib.

From The Guardian • Oct. 2, 2019

Dad had a good sense of theater, and he’d try to time this apparent ad lib so that it would coincide with the change in traffic.

From "Cheaper by the Dozen" by Frank B. Gilbreth Jr. and Ernestine Gilbreth Carey