fender vs auto

fender and auto both are nouns.

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

fender (noun)	auto (noun)
a cushion-like device that reduces shock due to an impact	a motor vehicle with four wheels; usually propelled by an internal combustion engine
a barrier that surrounds the wheels of a vehicle to block splashing water or mud
a low metal guard to confine falling coals to a hearth
an inclined metal frame at the front of a locomotive to clear the track