Thesaurus.com
Dictionary.com
Definitions

psychoactive

[sahy-koh-ak-tiv] / ˌsaɪ koʊˈæk tɪv /
ADJECTIVE
psychedelic
Synonyms
STRONGEST
hallucinatory kaleidoscopic multicolored
WEAK
consciousness-expanding crazy experimental freaky hallucinogenic mind-bending mind-blowing mind-changing mind-expanding psychotomimetic psychotropic trip
Antonyms
STRONGEST
monochrome
WEAK
normal

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.