défectueux Englisch:

Some diseases are caused by a defective gene.

It is totally unacceptable for operators to allow these vehicles on the road when they are defective.

I’ve just tried out three of the promotional DVDs and two were defective – they wouldn’t play at all.

... and instead use a defective implementation which disables the...

My printer's black ink is defective; it bleeds across the page if I touch it with my finger.