keep a civil tongue in one's head

Verb

idiomatic

(idiomatic) To maintain a polite manner of speaking.

Japanese Meaning

礼儀正しい言葉遣いを維持する / 丁寧な口調を保つ / 品位のある話し方を続ける

Even when criticizing a colleague, it's wise to keep a civil tongue in one's head to avoid unnecessary offense.

同僚を批判するときでさえ、余計な侮辱を避けるために礼儀正しい言葉遣いをするのが賢明だ。

Sense（1）

(idiomatic) To maintain a polite manner of speaking.

keeps a civil tongue in one's head

（ present singular third-person ）

keeping a civil tongue in one's head

（ participle present ）

kept a civil tongue in one's head

（ participle past ）

kept a civil tongue in one's head

（ past ）