To show off; to flaunt something deliberately to attract attention or boast about it.
彼は新しい時計を買うとすぐに友達に見せびらかした。
As soon as he bought the new watch, he immediately showed it off to his friends.
SNSで高級レストランの写真を見せびらかすのはやめたほうがいい。
You shouldn't flaunt photos of fancy restaurants on social media.
彼女は自分の成績を見せびらかすような言い方をした。
She spoke in a way that flaunted her grades.