dress up vs cosplay

dress up and cosplay both are verbs.

Word	Noun	Adjective	Verb	Adverb
dress up	No	No	Yes	No
cosplay	No	No	Yes	No

As verbs, cosplay is a hyponym of dress up; that is, cosplay is a word with a more specific, narrower meaning than dress up:

dress up: dress in a costume
cosplay: wear a costume to resemble a character from some media especially anime

dress up (verb)	cosplay (verb)
put on special clothes to appear particularly appealing and attractive	wear a costume to resemble a character from some media especially anime
dress in a costume
dress in a certain manner
make something appear superficially attractive
put a caparison on