extempore vs offhand

extempore and offhand both are adjectives.

Word	Noun	Adjective	Verb	Adverb
extempore	No	Yes	No	Yes
offhand	No	Yes	No	Yes

As adjectives, extempore and offhand are synonyms defined as:

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

extempore (adjective)	offhand (adjective)
with little or no preparation or forethought	casually thoughtless or inconsiderate
	with little or no preparation or forethought

extempore (adverb)	offhand (adverb)
without prior preparation	in a casually inconsiderate manner
	without previous thought or preparation