Complex sentence: Nail biting, also known as onychophagy or onychophagia, is an oral compulsive habit and is sometimes described as a parafunctional activity: the common use of the mouth for an activity other than speaking, eating, or drinking.
Split into simpler sentences: Nail biting, also known as onychophagy or onychophagia, is an oral compulsive habit. It is sometimes described as a parafunctional activity, the common use of the mouth for an activity other than speaking, eating, or drinking.