stiffen vs stiffen

stiffen and stiffen both are verbs.

Word	Noun	Adjective	Verb	Adverb
stiffen	No	No	Yes	No
stiffen	No	No	Yes	No

stiffen (verb)	stiffen (verb)
become stiff or stiffer	become stiff or stiffer
make stiff or stiffer	make stiff or stiffer
severely restrict in scope or extent	severely restrict in scope or extent