unrehearsed vs extemporaneous

unrehearsed and extemporaneous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unrehearsed	No	Yes	No	No
extemporaneous	No	Yes	No	No

As adjectives, unrehearsed and extemporaneous are synonyms defined as:

unrehearsed and extemporaneous: with little or no preparation or forethought

Other synonyms of unrehearsed include ad-lib, extemporary, extempore, impromptu, off-the-cuff, offhand, offhanded.

unrehearsed (adjective)	extemporaneous (adjective)
with little or no preparation or forethought	with little or no preparation or forethought