expression, godan verb (-u)
get into a fight; take up a challenge; accept a provocation
Idiomatic expression meaning to willingly accept or respond to a provocation, challenge, or fight instead of ignoring it. Often used when someone rises to the bait.
彼は相手の挑発に乗って喧嘩を買った。
He took the bait and got into a fight with the other person.
そんな言い方
If you're spoken to like that, you have no choice but to take up the challenge.