shitty vs rotten

shitty and rotten both are adjectives.

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

As adjectives, shitty and rotten are synonyms defined as:

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

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