kerchief vs neckerchief

kerchief and neckerchief both are nouns.

Word	Noun	Adjective	Verb	Adverb
kerchief	Yes	No	No	No
neckerchief	Yes	No	No	No

As nouns, neckerchief is a hyponym of kerchief; that is, neckerchief is a word with a more specific, narrower meaning than kerchief:

kerchief: a square scarf that is folded into a triangle and worn over the head or about the neck
neckerchief: a kerchief worn around the neck

Other hyponyms of kerchief include headscarf.

kerchief (noun)	neckerchief (noun)
a square scarf that is folded into a triangle and worn over the head or about the neck	a kerchief worn around the neck