Limber

The word limber has two very distinct meanings in current English - as we3ll as one distinctly specialized one.

• The adjective limber means 'flexible', 'pliant', 'easily bent'; and, applied to people (its most common current application) 'fit', 'lithe' 'nimble'. Gymnasts are commonly very limber.
  • From this comes the phrasal verb 'to limber up', 'to loosen one's muscles and joints by preparatory exercises [before such events as a gymnastic tournament]', 't warm up'.
• The noun 'a limber' means a two-wheeled carriage used to support a heavy gun while it is being moved. The limber supports the trail of an artillery piece, which is principally designed to stop movement as a result of recoil when the piece is fired; to enable smooth movement of the piece while it is being transported, the trail must be kept clear of the ground. This is the function of the limber, which in turn is attached to the propulsion unit - historically, a team of horses; more recently motor transport units, or tractors. Most recently, the tendency has been to make all heavy weapons self-propelled. The limber has usually contained a small supply of ready-use ammunition.
  • In the context of artillery, 'to limber up' means to prepare a gun for movement by attaching it to its limber. The reverse process - unhitching a gun, as for to prepare for an engagement, is unlimbering (not 'to limber down'.
• In ships and boats, limbers, or limber-holes, are holes cut in the frames of a hull to allow water to drain freely along the length of the bilges and run towards the well from which the pumps may extract it.

Don't allow yourself to confuse either of these words with lumber.