tunnel vs auto

tunnel and auto both are nouns.

Word	Noun	Adjective	Verb	Adverb
tunnel	Yes	No	Yes	No
auto	Yes	No	No	No

tunnel (noun)	auto (noun)
a passageway through or under something, usually underground (especially one for trains or cars)	a motor vehicle with four wheels; usually propelled by an internal combustion engine
a hole made by an animal, usually for shelter

tunnel (verb)	auto (verb)
force a way through
move through by or as by digging