na-adjective
proud; boastful; bragging; conceited
Describes a person's manner or expression as openly proud or self-satisfied, often with a hint of showing off. Used as a な-adjective.
彼は自慢気に新しい車を見せびらかした。
He proudly showed off his new car.
自慢気な顔をしているね。
You have a smug look on your face.
Compound of 自慢 (じまん, 'boast, pride') and the suffix 気/げ (げ, '-like, seeming').