English translation of 擅自
take it upon oneself (pt took) (pp taken)
⇒ 上司不在,他擅自和客户签了协议。(Shàngsi bù zài, tā shànzì hé kèhù qiānle xiéyì.)
Since the boss was out, he took it upon himself to sign the agreement.
Translation of 擅自 from the Collins Chinese to English Dictionary