1. A large portion of fat caused by one's breasts and stomach combining, usually found in an enormously obese individual. Typically a woman or a fat man with bitch-tits.
2. An obesely fat person who does nothing but eat and take up space. Someone who is a strain on his/her co-workers, relatives, and friends - if any exist. Usually smells like previously eaten food.
"I better lose weight before I grow a bommoch!"
"That bitch is acting like a bommoch, and we want her to die"