"Gat one's face" is not a word but a phrase meaning to stare at someone with a threatening or angry expression. Some antonyms for this phrase are to smile warmly, to look away, to avert one's gaze, to be friendly or approachable, to extend a hand for a handshake, to give a compliment or a kind word, to show empathy or understanding, to forgive, or to ignore the other person altogether. These actions foster positive communication and relationship-building and can diffuse tension or aggression in a conflict. Therefore, choosing the right antonym for "gat one's face" can go a long way in creating harmony and establishing rapport with others.