by fair means or foul就是通过各种不管好还的方法手段，也就是不择手段，千方百计，采取一切手段地。

【例句】
She's determined to win, by fair means or foul.
她决心要赢，哪怕是不择手段。

Smith is determined to get on is this world, by fair means or foul.
史密斯决心，要不择手段出人头地。