backside vs trunk

backside and trunk both are nouns.

Word	Noun	Adjective	Verb	Adverb
backside	Yes	No	No	No
trunk	Yes	No	No	No

backside (noun)	trunk (noun)
the fleshy part of the human body that you sit on	a long flexible snout as of an elephant
the side of an object that is opposite its front	luggage consisting of a large strong case used when traveling or for storage
	compartment in an automobile that carries luggage or shopping or tools
	the body excluding the head and neck and limbs
	the main stem of a tree; usually covered with bark; the bole is usually the part that is commercially useful for lumber