Spanker \Spank"er\, n.

1. One who spanks, or anything used as an instrument for spanking.

2. (Naut.) The after sail of a ship or bark, being a fore-and-aft sail attached to a boom and gaff; -- sometimes called driver. See Illust. under Sail. --Totten.

3. One who takes long, quick strides in walking; also, a fast horse. [Colloq.]

4. Something very large, or larger than common; a whopper, as a stout or tall person. [Colloq.]

Spanker boom (Naut.), a boom to which a spanker sail is attached. See Illust. of Ship.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Driver \Driv"er\, n. [From Drive.]

1. One who, or that which, drives; the person or thing that urges or compels anything else to move onward.

2. The person who drives beasts or a carriage; a coachman; a charioteer, etc.; hence, also, one who controls the movements of a locomotive.

3. An overseer of a gang of slaves or gang of convicts at their work.

4. (Mach.) A part that transmits motion to another part by contact with it, or through an intermediate relatively movable part, as a gear which drives another, or a lever which moves another through a link, etc. Specifically:
   (a) The driving wheel of a locomotive.
   (b) An attachment to a lathe, spindle, or face plate to turn a carrier.
   (c) A crossbar on a grinding mill spindle to drive the upper stone.

5. (Naut.) The after sail in a ship or bark, being a fore-and-aft sail attached to a gaff; a spanker. --Totten.

Driver ant (Zo["o]l.), a species of African stinging ant; one of the visiting ants (Anomma arcens); -- so called because they move about in vast armies, and drive away or devour all insects and other small animals.

Source: Webster's Revised Unabridged Dictionary (1913)