treacherous Copy link Outline 1. perfĭdus (breaking through faith obligations)2. perfĭdiōsus (habitually t.)3. infīdus, infĭdēlis (more freq. in good prose than precedd.)4. mălĕfīdus (poet.)5. subdŏlus (that hides secret designs6. dŏlōsus (full of deceits and wiles) • treacherous: 1. perfĭdus (breaking through faith obligations): Cic. Off. 3, 14, extr. (but the word is rare in the best prose): t. arms (war), p. bella, Ov. F. 4, 380. Fig.: t. waters, p. freta, Sen. trag. 2. perfĭdiōsus (habitually t.): Cic. Join: fallax, perfidiosus, perfidiosus et insidiosus et fallax, Cic.: perfidiosus et subdolus animo, Tac. 3. infīdus, infĭdēlis (more freq. in good prose than precedd.): v. unfaithful, faithless. 4. mălĕfīdus (poet.): Virg. Aen. 2, 23 (statio m. carinis). 5. subdŏlus (that hides secret designs: sly, cunning): Sall.: Tac. 6. dŏlōsus (full of deceits and wiles): Hor.: Ov. Fig.: t. embers, cinis d.. Hor. Od. 2, 1, 7. Phr.: to be on t. (slippery, unsafe) ground, in lubrico versari, Cic. Or. 28, 98: v. slippery.