roach vs cockroach

roach and cockroach both are nouns.

Word	Noun	Adjective	Verb	Adverb
roach	Yes	No	Yes	No
cockroach	Yes	No	No	No

As nouns, roach and cockroach are synonyms defined as:

roach and cockroach: any of numerous chiefly nocturnal insects; some are domestic pests

roach (noun)	cockroach (noun)
any of numerous chiefly nocturnal insects; some are domestic pests	any of numerous chiefly nocturnal insects; some are domestic pests
European freshwater food fish having a greenish back
the butt of a marijuana cigarette
street names for flunitrazepam
a roll of hair brushed back from the forehead

roach (verb)	cockroach (verb)
cut the mane off (a horse)
comb (hair) into a roach