Unhallowed; defiled by something unholy, either physically by an objectionable substance, or morally by guilt or sin
Unchaste; obscene (not according to or not abiding by some system of sexual morality)
Containing undesired intermixtures
Insufficiently cooked, so as to be unpalatable or inedible.
Very lightly cooked.
The broccoli was nicely undercooked.
Done with insufficient energy, enthusiasm, etc.