sumo vs rassling

sumo and rassling both are nouns.

Word	Noun	Adjective	Verb	Adverb
sumo	Yes	No	No	No
rassling	Yes	No	No	No

As nouns, rassling is a hypernym of sumo; that is, rassling is a word with a broader meaning than sumo:

sumo: a Japanese form of wrestling; you lose if you are forced out of a small ring or if any part of your body (other than your feet) touches the ground
rassling: the sport of hand-to-hand struggle between unarmed contestants who try to throw each other down

Other hypernyms of sumo include sport, grappling, wrestling.

sumo (noun)	rassling (noun)
a Japanese form of wrestling; you lose if you are forced out of a small ring or if any part of your body (other than your feet) touches the ground	the sport of hand-to-hand struggle between unarmed contestants who try to throw each other down