rump vs behind

rump and behind both are nouns.

Word	Noun	Adjective	Verb	Adverb
rump	Yes	No	No	No
behind	Yes	Yes	No	Yes

As nouns, rump and behind are synonyms defined as:

rump (noun)	behind (noun)
the part of an animal that corresponds to the human buttocks	the fleshy part of the human body that you sit on
the fleshy part of the human body that you sit on
fleshy hindquarters; behind the loin and above the round

rump (adjective)	behind (adjective)
	having the lower score or lagging position in a contest

rump (adverb)	behind (adverb)
	in or to or toward the rear
	remaining in a place or condition that has been left or departed from
	in debt
	in or into an inferior position
	showing a time that is earlier than the actual time