/ ˌæd ˈlɪb; NAmE / verb
( -bb- ) to say sth in a speech or a performance that you have not prepared or practised
SYN improvise :
[ v ]
She abandoned her script and began ad-libbing.
[ vn ]
I lost my notes and had to ad-lib the whole speech.
► ad lib noun :
The speech was full of ad libs.
► ad lib adjective :
an ad lib speech
► ad lib adverb :
She delivered her lines ad lib.
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WORD ORIGIN
early 19th cent. (as an adverb): abbreviation of ad libitum .