BOY - Male servant.
TOO - Likewise.
COO - The murmuring sound made by a dove or pigeon.
COT - A symbol of the trigonometric function cotangent.
BOO - A loud exclamation intended to scare someone, especially a child. Usually used when one has been hidden from the victim and then suddenly appeared unexpectedly.
BOT - The larva of a bot fly, which infests the skin of various mammals, producing warbles, or the nasal passage of sheep, or the stomach of horses.
COB - A male swan.
COY - Bashful, shy, retiring.
BOOT - A heavy shoe that covers part of the leg.
COOT - Any of various aquatic birds of the genus Fulica that are mainly black with a prominent frontal shield on the forehead.
TOOT - The noise of a horn or whistle.
BOOTY - A form of prize which, when a ship was captured at sea, could be distributed at once.
BOYCOTT - To abstain, either as an individual or group, from using, buying, or dealing with someone or some organization as an expression of protest.