Merriam-Webster's Collegiate® Dictionary, 11th Edition
LIMBER
I. noun
Etymology: Middle English lymour
Date: 15th century
a two-wheeled vehicle to which a gun or caisson may be attached,
II. adjective
Etymology: origin unknown
Date: 1565
capable of being shaped ; flexible , having a supple and resilient quality (as of mind or body) ; agile , nimble , limberly adverb limberness noun
III. verb (limbered; limbering)
Date: 1748
transitive verb to cause to become limber , intransitive verb to become limber