bri·dle / ˈbrīdl/ • n. the headgear used to control a horse, consisting of buckled straps to which a bit and reins are attached. ∎  a line, rope, or device that is used to restrain or control the action or movement of something.• v. 1. [tr.] (usu. be bridled) put a bridle on (a horse). ∎  bring (something) under control; curb: the fact that he was their servant bridled his tongue.2. [intr.] show one's resentment or anger, esp. by throwing up the head and drawing in the chin: ranchers have bridled at excessive federal control.

bridle

bridle OE. brīdel = OFris. brīdel, (M)Du, breidel, OHG. brittil; WGmc. deriv. of *breʒd-; see BRAID, -LE1.
Hence bridle vb. OE. brīdlian.