有隙可乘指做事情考虑不周密使别人能找出漏洞加以利用。例今魏有隙可乘不就此时伐之更待何时?——《三国演义》英there is a crack to squeeze through; fulnerable;
无隙可乘无懈可击;没有可钻的空子。英no crack to get in by; no chink in sb.'s armour; no loophole to exploit; no weakness to take advantage of;
可乘之机可以乘势行动作为的机遇。例不给敌人可乘之机。英avail oneself of the opportunity; an opportunity that can be exploited;