[ ad-lib, ad- ]
/ ædˈlɪb, ˈæd- /

verb (used with object), ad-libbed, ad-lib·bing.

to improvise all or part of (a speech, a piece of music, etc.): to ad-lib one's lines.

verb (used without object), ad-libbed, ad-lib·bing.

to act, speak, etc., without preparation: Throughout the play he had to ad-lib constantly.


impromptu; extemporaneous: ad-lib remarks to hecklers.

Origin of ad-lib

1915–20, Americanism; v. use of ad lib


ad-lib·ber, noun

Definition for ad-lib (2 of 3)

ad lib
[ ad lib, ad ]
/ æd ˈlɪb, ˈæd /


something improvised in speech, music, etc.: Was that joke part of your speech or an ad lib?


at one's pleasure; without restriction.
freely; as needed; without stint: Water can be given to the patients ad lib.

Origin of ad lib

First recorded in 1810–20; see origin at ad libitum

Definition for ad-lib (3 of 3)

ad lib. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ad-lib

British Dictionary definitions for ad-lib

Derived forms of ad-lib

ad-libber, noun

Word Origin for ad-lib

C18: short for Latin ad libitum, literally: according to pleasure
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for ad-lib

ad lib.


ad libitum (freely, as desired)
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.