(informal) A blunder, an error.

(baseball, slang) A fly ball that is weakly hit just over the infielders.

(film, informal) A filmed or videotaped outtake that has recorded an amusing accident and/or mistake.

(nautical) A gaff-rigged fore-and-aft sail set from and aft of the aftmost mast of a square-rigged ship; a spanker.

(US, military, slang) The Vietnam-era M79 grenade launcher (due to its distinctive report).