drink vs drink down

drink is a noun but drink down is not a noun.

Word	Noun	Adjective	Verb	Adverb
drink	Yes	No	Yes	No
drink down	No	No	Yes	No

As verbs, drink down is a hyponym of drink; that is, drink down is a word with a more specific, narrower meaning than drink:

drink (noun)	drink down (noun)
the act of drinking alcoholic beverages to excess
the act of swallowing
any liquid suitable for drinking
a single serving of a beverage
any large deep body of water

drink (verb)	drink down (verb)
be fascinated or spell-bound by; pay close attention to	drink down entirely
take in liquids
consume alcohol
drink excessive amounts of alcohol; be an alcoholic
propose a toast to