Retailers can return defective merchandise.零售商可退回残次商品。

Her eyesight was becoming defective.她的视力开始出现问题。

The old woman was either a criminal or mentally defective.这名老妇不是罪犯, 就是脑筋有问题。

I enunciated slowly, as if speaking to a mental defective.我放慢速度一字一顿, 就像是在对一个傻子说话一样。