PRO'NENESS, n. The state of bending downwards; opposed to the erectness of man. 1. The state of lying with the face downwards; contrary to supineness. 2. Descent; declivity; as the proneness of a hill. 3. Inclination of mind, heart or temper; propension; disposition; as the proneness of the Israelites to idolatry; proneness to self-gratification or to self-justification; proneness to comply with temptation; sometimes in a good sense; as ;the proneness of good men to commiserate want.