1. Gargantuan, immense (adj.)
2. 10,000 motherfuckers (interjection)
3. A mean-ass swamp monster, specifically a mythical alligator with two heads. (noun)
4. Euphemism for motherfucker (used along the gulf coast by African Americans)
Man, that shit is motengator!
That sumbitch is one fat motengator; he can't even fit through the door.
Southern slang explicitive used in substitution to generally mean "bitch ass mother-fucker" or other explicitive. Used on subject who will most likely snitch or write you up if real explicitive is used.