late 14c., "shaped like a club, thick at the end," from club (n.). Specifically of defects of the foot by c. 1500; meaning "formed into a club" is from 1620s.
name of a club founded by Whig politicians in London (Addison and Steele were members), 1703; so called from Christopher ("Kit") Catling, or a name similar to it, a tavernkeeper or pastry cook in London, in whose property the club first met. Hence "a size of portrait less than half length in which a hand may be shown" (1754), supposedly is because the dining room in which portraits of club members hung was too low for half-length portraits.
"small, narrow-headed iron golf club," used to get the ball out of ruts or other bad places, 1857, of obscure origin.
"short, thick stick used as a weapon," Old English cycgel "club with rounded head;" perhaps from PIE *geu- "to curve, bend."
1736, "to dose on pills," from pill (n.). From 1882 as "to form into pills." In club slang, "to reject by vote, blackball" (1855). Related: Pilled; pilling.