halfback vs eleven

halfback and eleven both are nouns.

Word	Noun	Adjective	Verb	Adverb
halfback	Yes	No	No	No
eleven	Yes	Yes	No	No

halfback (noun)	eleven (noun)
(American football) the position of a back on a football team, generally smaller in size than a fullback	a team that plays football
(football) the running back who plays the offensive halfback position	the cardinal number that is the sum of ten and one

halfback (adjective)	eleven (adjective)
	being one more than ten