A defense raised in a responsive pleading (answer) relating a new matter as a defense to the complaint; affirmative defenses might include contributory negligence or estopped in civil actions; in criminal cases insanity, duress, or self-defense might be used.
An "affirmative defense" is a legally permissible reason for basing an employment decision on an individual's protected basis. For example, it permits an employer to admit that he did not promote an individual because of his/her disability as long as the employer can prove that its conduct is excused by a special provision in the law. The affirmative defenses that follow apply primarily to employment discrimination.
A defense which will negate criminal blameworthiness even if it is proven that the defendant committed the alleged acts. (e.g., self-defense, insanity, and necessity); the defendant bears the burden of production.