bread knife vs knife

bread knife and knife both are nouns.

Word	Noun	Adjective	Verb	Adverb
bread knife	Yes	No	No	No
knife	Yes	No	Yes	No

As nouns, knife is a hypernym of bread knife; that is, knife is a word with a broader meaning than bread knife:

bread knife: a knife used to cut bread
knife: edge tool used as a cutting instrument; has a pointed blade with a sharp edge and a handle

bread knife (noun)	knife (noun)
a knife used to cut bread	edge tool used as a cutting instrument; has a pointed blade with a sharp edge and a handle
	a weapon with a handle and blade with a sharp point
	any long thin projection that is transient

bread knife (verb)	knife (verb)
	use a knife on