[vahy-per] 
| 1. | any of several venomous Old World snakes of the genus Vipera, esp. V. berus, a small snake common in northern Eurasia. |
| 2. | any related snakes belonging to the family Viperidae, characterized by erectile, venom-conducting fangs. |
| 3. | pit viper. |
| 4. | any of various venomous or supposedly venomous snakes. |
| 5. | a malignant or spiteful person. |
| 6. | a false or treacherous person. |
| 7. | (initial capital letter ) Military. a 9-pound (4 kg), shoulder-launched, unguided U.S. Army antitank rocket with an effective range of 273 yds. (250 m). |
| 8. | to nourish a viper in one's bosom, to befriend a person who proves to be treacherous. |
| vi·per·ish (vī'pər-ĭsh) adj. Spiteful or malicious; venomous: a viperish retort. |