stiffen vs loosen

stiffen and loosen both are verbs.

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

stiffen (verb)	loosen (verb)
become stiff or stiffer	become loose or looser or less tight
make stiff or stiffer	make loose or looser
severely restrict in scope or extent	make less dense
	disentangle and raise the fibers of
	cause to become loose
	become less severe or strict
	make less severe or strict