顔(かお)をつぶすto make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish

母(はは)：「親(おや)の顔(かお)をつぶす事(こと)をするな！」

Mother: "Don't do anything that would embarrass your parents!" {to make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish}

上司(じょうし)の顔(かお)をつぶした事(こと)を反省(はんせい)しています。

I am reflecting on the fact that I made my boss lose face. {to make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish}

同僚(どうりょう)の顔(かお)をつぶさないように、後(あと)でこっそり誤(あやま)りを指摘(してき)する。

In order not to make my colleague lose face, I will discreetly point out the mistake later. {to make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish}

試合(しあい)に惨敗(ざんぱい)してしまったことで、監督(かんとく)の顔(かお)をつぶしてしまいました。

Due to the devastating loss in the match, I ended up causing the coach to lose face. {to make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish}

弟子(でし)たる者(もの)、師匠(ししょう)の顔(かお)をつぶさないように最大限(さいだいげん)の努力(どりょく)をするべきです。

A disciple should make the utmost effort not to embarrass their master or make them look foolish. {to make somebody lose face, to cause loss of face, to embarrass someone, to make someone look foolish}