Merriam-Webster's Collegiate® Dictionary, 11th Edition
JIB
I. noun
Etymology: origin unknown
Date: 1661
a triangular sail set on a stay extending usually from the head of the foremast to the bowsprit or the jibboom,
II. noun
Etymology: probably by shortening & alteration from gibbet
Date: 1764
the projecting arm of a crane, a derrick boom,
III. intransitive verb (jibbed; jibbing)
Etymology: probably from jib to shift from one side of a ship to the other, perhaps from 1jib
Date: 1811
to refuse to proceed further ; balk , jibber noun