tripper vs drug user

tripper and drug user both are nouns.

Word	Noun	Adjective	Verb	Adverb
tripper	Yes	No	No	No
drug user	Yes	No	No	No

As nouns, drug user is a hypernym of tripper; that is, drug user is a word with a broader meaning than tripper:

tripper: (slang) someone who has taken a psychedelic drug and is undergoing hallucinations
drug user: a person who takes drugs

Other hypernyms of tripper include substance abuser, user.

tripper (noun)	drug user (noun)
a catch mechanism that acts as a switch	a person who takes drugs
a tourist who is visiting sights of interest
a walker or runner who trips and almost falls
(slang) someone who has taken a psychedelic drug and is undergoing hallucinations