extemporize vs improvise

extemporize and improvise both are verbs.

Word	Noun	Adjective	Verb	Adverb
extemporize	No	No	Yes	No
improvise	No	No	Yes	No

As verbs, extemporize and improvise are synonyms defined as:

Other synonyms of extemporize include ad-lib, extemporise, improvize.

As verbs, extemporize and improvise are synonyms defined as:

extemporize and improvise: manage in a makeshift way; do with whatever is at hand

extemporize (verb)	improvise (verb)
perform without preparation	perform without preparation
manage in a makeshift way; do with whatever is at hand	manage in a makeshift way; do with whatever is at hand