smack talk

slang uncountable

(slang) Insulting speech, especially when intended to irritate or annoy someone.

Japanese Meaning

（俗語）相手を刺激・挑発する目的で発せられる侮辱的な言葉、口上 / 相手を怒らせる、または不快にさせるための挑発的な暴言や悪口

After the game, his nonstop smack talk ruined the post-match handshake.

試合後、彼の絶え間ない挑発的な発言が握手を台無しにした。

Sense（1）

(slang) Insulting speech, especially when intended to irritate or annoy someone.