Wordnet 3.0
NOUN (1)
1. 
 a highly lethal nerve agent used in chemical warfare; 
 a toxic liquid that penetrates the skin or lungs to disrupt the nervous system and stop respiration; 
 in combat VX gas is deployed by detonating a container over the target area and can persist in the environment up to several weeks after release; 
- Example: "VX gas is one of those things we wish we could disinvent"
WordNet (r) 3.0 (2006):
VX gas
    n 1: a highly lethal nerve agent used in chemical warfare; a
         toxic liquid that penetrates the skin or lungs to disrupt
         the nervous system and stop respiration; in combat VX gas
         is deployed by detonating a container over the target area
         and can persist in the environment up to several weeks
         after release; "VX gas is one of those things we wish we
         could disinvent"