terbinafine /tɚˈbɪn.əˌfin/ noun1 •A synthetic allylamine antifungal drug that is highly lipophilic, used in the form of its hydrochloride C₂₁H₂₅N·HCl orally in the treatment of onychomycosis and topically in the treatment of tinea corporis, tinea cruris, and athlete's foot.