ad-lib, extemporaneous, extemporary, extempore, impromptu, offhand, offhanded, off-the-cuff, unrehearsed(adj)

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"

offhand, offhanded(adverb)

casually thoughtless or inconsiderate

"an offhand manner"; "she treated most men with offhand contempt"

offhand, offhanded, offhandedly(adverb)

without previous thought or preparation

"couldn't give the figures offhand"; "we decided offhand to go to Canada"; "she had made these remarks offhandedly"

offhand, offhanded, offhandedly(adverb)

in a casually inconsiderate manner

"replied offhand, his mind a million miles away"; "she threw him over offhandedly without even a Dear-John letter"

offhanded(Adjective)

in a casual or curt style, without preparation or thought