プログレッシブ和英中辞典(第4版)の解説
そむく【背く】
❶〔従わない〕disobey; go against
命令に背く
disobey [disregard] an order
一郎は親の意に背いて俳優になった
Ichiro 「disobeyed his parents [went against his parents' wishes] and became an actor.／Ichiro became an actor against his parents' wishes.
上司に背く
「rebel against [betray] one's superior
妻に背かれて彼はやけになっていた
〔裏切られて〕He was in a desperate mood, having been betrayed by his wife.
❷〔違反する〕
約束に背く
break one's word
それでは規則に背くことになります
That would 「be against [break/infringe on] the rules.
❸〔予想されたことと反対になる〕
人の期待に背く
be [act] contrary to a person's expectations
山田の最新作は彼の評判に背かない出来栄えだ
Yamada's latest work 「lives up to [is worthy of/justifies] his reputation.