Hi, I'm Jina. 갬성 is actually 감성 which means sensitivity. 갬성 sounds like when foreigners try to say 감성. Somehow it became a Korean slang word. ex) 인스타갬성 (instagrammable: A picture that is worth posting on Instagram) 새벽갬성 (twilighting: Being so into something that you're completely unaware of your surroundings) I hope it will help you (: