cowl vs bonnet

cowl and bonnet both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowl	Yes	No	Yes	No
bonnet	Yes	No	Yes	No

As nouns, cowl and bonnet are synonyms defined as:

cowl and bonnet: protective covering consisting of a metal part that covers the engine

Other synonyms of cowl include cowling, hood.

cowl (noun)	bonnet (noun)
protective covering consisting of a metal part that covers the engine	a hat tied under the chin
a loose hood or hooded robe (as worn by a monk)	protective covering consisting of a metal part that covers the engine

cowl (verb)	bonnet (verb)
cover with or as with a cowl	dress in a bonnet