What is another word for acid head?
Pronunciation: [ˈasɪd hˈɛd] (IPA) 
The term "acid head" is quite derogatory and offensive, therefore, it is important to use synonyms which are more polite and acceptable. "Psychedelic enthusiast" is a suitable alternative which focuses on the person's interest in psychedelic substances, while avoiding any negative connotations. "Hallucinogenic drug user" is also a more neutral term, describing the person's drug use without labelling them in a negative way. Another synonym that can be used is "psychedelic user" which is less offensive and more accurate. "Tripper" is a casual and less loaded term that can be used to describe an individual who frequently uses hallucinogenic substances.
