Home › Words › P › phenibutphenibut/ˈfɛnɪbjuːt/phenibut means β-phenyl-GABA, a gabapentinoid drug similar to baclofen and gabapentin, often legally sold online and taken orally for its euphoric effects.phenibut is pronounced /ˈfɛnɪbjuːt/.EtymologyFrom phen(yl) + -i- + but(yric acid).nounβ-phenyl-GABA, a gabapentinoid drug similar to baclofen and gabapentin, often legally sold online and taken orally for its euphoric effects.Definitions & examples from Wiktionary (CC BY-SA 3.0).