E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Jib.
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.
1
Jib. The under-lip. A sailor’s expression; the under-lip indicating the temper, as the jib indicates the character of a ship.
2
The cut of his jib. A sailor’s phrase, meaning the expression of a person’s face. Sailors recognise vessels at sea by the cut of the jibs.
3
To hang the jib. The jib means the lower lip. To hang the lower lip is to look ill-tempered, or annoyed.
