(n.)That audible, nasty, rumbling sound created from holding in flatulence, most of the time uncontrollable except by avoiding gassy food in the first place. Although infarts do not smell, it's very embarassing in public since it can be quite similar to a real fart.
(v.)To sound an infart
A: Did you just infarted?
B: Yeah, guess I held it in for to long.
A: And why does it smell anyway?
B: Oh well...uh, bye.