1. (n.) The face one makes when they exclaim, "Boom!".
2. (interj.) Exactly like exclaiming "Boom!" This works because it conjures the mental image of the face you would have made had you just said, "Boom!" (Note: typically is performed without actually making a boomface.)
A pet name used to address one, to whom you have much affection for. Couples who use this term are often immulated by jealous or rival couples, in attempts to give themselves false hope of becomming the original booface-using duo.