heavyweight vs gladiator

heavyweight and gladiator both are nouns.

Word	Noun	Adjective	Verb	Adverb
heavyweight	Yes	No	No	No
gladiator	Yes	No	No	No

As nouns, gladiator is a hypernym of heavyweight; that is, gladiator is a word with a broader meaning than heavyweight:

Other hypernyms of heavyweight include prizefighter.

heavyweight (noun)	gladiator (noun)
A weight class division in combat sports, often the heaviest.	(ancient Rome) a professional combatant or a captive who entertained the public by engaging in mortal combat
a person of exceptional importance and reputation	a professional boxer
a professional boxer who weighs more than 190 pounds
a wrestler who weighs more than 214 pounds
a very large person; impressive in size or qualities
an amateur boxer who weighs no more than 201 pounds