c. 1300, "legal condition of a serf or slave," from Middle English bond "a serf, tenant farmer," from Old English bonda "householder," from or cognate with Old Norse boandi "free-born farmer," noun use of present participle of boa "dwell, prepare, inhabit," from PIE *bhow-, from root *bheue- "to be, exist, grow." For sense evolution, see bond (adj.). The sexual sado-masochism sense is recorded by 1963 (in a New York law against publications portraying it).
The Boer War (1899-1902), in which Great Britain defeated the South African Republic of Transvaal and Orange Free State, was technically the Second Boer War, there having been a brief preview 1880-1881.
"A word of involved history in and out of English, though the ultimate etymology is clear enough" [OED]. In English it often was applied to agricultural laborers in or from other lands, as opposed to the native yeoman; negative transferred sense "one who is rude in manners" attested by 1560s (in boorish), from notion of clownish rustics. Related: Boorishness.