na-adjective
boastful; arrogant; presumptuous
Describes someone who talks big, brags, or speaks arrogantly. Often used for a person's character or manner of speaking.
彼は舌長な態度で自分の成功を自慢した。
He boasted about his success with an arrogant attitude.
あの人の舌長な話し方は聞いていて不愉快だ。
That person's boastful way of speaking is unpleasant to listen to.
Compound of 舌 (tongue) and 長 (long), literally 'long-tongued', figuratively describing someone who talks too much or boasts. The exact historical derivation is uncertain.