old school tie vs necktie

old school tie and necktie both are nouns.

Word	Noun	Adjective	Verb	Adverb
old school tie	Yes	No	No	No
necktie	Yes	No	No	No

As nouns, necktie is a hypernym of old school tie; that is, necktie is a word with a broader meaning than old school tie:

old school tie: necktie indicating the school the wearer attended
necktie: neckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front

Other hypernyms of old school tie include tie.

old school tie (noun)	necktie (noun)
necktie indicating the school the wearer attended	neckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front