(1):

(n.) Opposition; contradiction; as between differing or contending interests, views, purposes, etc.

(2):

(n.) A loud noise resulting from collision; a noisy collision of bodies; a collision.

(3):

(v. i.) To meet in opposition; to act in a contrary direction; to come onto collision; to interfere.

(4):

(v. i.) To make a noise by striking against something; to dash noisily together.

(5):

(v. t.) To strike noisily against or together.