Both are abbreviations of ad libitum which is Latin for "at liberty." Ad-lib, with a hyphen, the commoner term, is a noun or verb meaning... ... lists 'ad-lib' as verb, adjective and 'ad lib' as noun, adverb.

How do you spell Adlive?

at one's pleasure; without restriction.

How do you use ad-lib in a sentence?

Ad-lib in a Sentence

1. Hannah completely forgot the speech she had prepared for class, so she had no choice but to ad-lib it and hope for the best. 2. Personally I find comedians that can ad-lib on stage much funnier than the ones who try to memorize a routine prior to performing.