ad-lib

nouns

remark made spontaneously without prior preparation
"his ad-libs got him in trouble with the politicians"
ad-lib
is a type of (narrower)
a statement that expresses a personal opinion or belief or adds information
"from time to time she contributed a personal comment on his account"
comment, input, remark

verbs

perform without preparation
"he extemporized a speech at the wedding"
ad-lib, extemporise, extemporize, improvise, improvize

adjectives

with little or no preparation or forethought
"his ad-lib comments showed poor judgment"; "an extemporaneous piano recital"; "an extemporary lecture"; "an extempore skit"; "an impromptu speech"; "offhand excuses"; "trying to sound offhanded and reassuring"; "an off-the-cuff toast"; "a few unrehearsed comments"
ad-lib, extemporaneous, extemporary, extempore, impromptu, off-the-cuff, offhand, offhanded, unrehearsed
said or done without having been planned or written in advance
"he made a few ad-lib remarks"
ad-lib, spontaneous, unwritten