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.
improvise, extemporize, impromptu, improvised, invent, extemporaneous, extempore, made-up, spontaneous, unprepared, unrehearsed, off-the-cuff, extemporaneously, spontaneously
Origin of ad-lib
1915–20, Americanism; v. use of ad lib
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
verb -libs, -libbing or -libbed
to improvise and deliver without preparation (a speech, musical performance, etc)
adjective (ad lib when predicative)
adverb ad lib
an improvised performance, often humorous
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