crappy vs rotten

crappy and rotten both are adjectives.

Word	Noun	Adjective	Verb	Adverb
crappy	No	Yes	No	No
rotten	No	Yes	No	No

As adjectives, crappy and rotten are synonyms defined as:

Other synonyms of crappy include icky, lousy, shitty, stinking, stinky.

crappy (adjective)	rotten (adjective)
very bad	having decayed or disintegrated; usually implies foulness
	damaged by decay; hence unsound and useless
	very bad