Definitions for "Ad-lib"
30 or 60 seconds long, an ad-lib is an announcer-read promotion of an advertiser's product from bullet points supplied by a client.
remark made spontaneously without prior preparation; "his ad-libs got him in trouble with the politicians"
perform without preparation; "he extemporized a speech at the wedding"
Unplanned words or phrases spoken during a presentation.
making up a line not originally in a play, usually done when an actor forgets a line or someone misses an entrance.