1. contentedly confident of one's ability, superiority, or correctness; complacent. 2. trim; spruce; smooth; sleek. 3. Exhibiting or feeling great or offensive satisfaction with oneself or with one's situation; self-righteously complacent
so if he saying you are too smugly he probably means you are to confident or to good for him. I think he meant you are snobby or you think to highly of yourself and if he doesn't know you personally and he says that about you, then he is an idiot.
Im going to start selling shirts that says "Don't hate me cause I'm Smugly" lol