E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
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 ships head to leeward.
Jib. The under-lip. A sailors expression; the under-lip indicating the temper, as the jib indicates the character of a ship.
The cut of his jib. A sailors phrase, meaning the expression of a persons face. Sailors recognise vessels at sea by the cut of the jibs.
To hang the jib. The jib means the lower lip. To hang the lower lip is to look ill-tempered, or annoyed.