piranha vs attacker

piranha and attacker both are nouns.

Word	Noun	Adjective	Verb	Adverb
piranha	Yes	No	No	No
attacker	Yes	No	No	No

As nouns, attacker is a hypernym of piranha; that is, attacker is a word with a broader meaning than piranha:

Other hypernyms of piranha include aggressor, assailant, assaulter.

piranha (noun)	attacker (noun)
small voraciously carnivorous freshwater fishes of South America that attack and destroy living animals	someone who attacks
someone who attacks in search of booty