blocker vs football player

blocker and football player both are nouns.

Word	Noun	Adjective	Verb	Adverb
blocker	Yes	No	No	No
football player	Yes	No	No	No

As nouns, football player is a hypernym of blocker; that is, football player is a word with a broader meaning than blocker:

blocker: a football player whose responsibility is to block players attempting to stop an offensive play
football player: an athlete who plays American football

Other hypernyms of blocker include footballer.

blocker (noun)	football player (noun)
a class of drugs that inhibit (block) some biological process	an athlete who plays American football
a football player whose responsibility is to block players attempting to stop an offensive play