A triangular sail borne in front of the foremast. It has the bowsprit for a base in small vessels, and the jib-boom in larger ones, and exerts an important effect, when the wind is abeam, in throwing the ship's head to leeward.
To hang the jib. The jib means the lower lip. To hang the lower lip is to look ill-tempered, or annoyed.
(To). To start aside; a “jibbing horse” is one that is easily startled. It is a sea term, to jib being to shift the boomsail from one side of the mast to the other.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894