c.1200, "dull, obtuse," perhaps from O.N.
blundra (see
blunder). Meaning "abrupt of speech or manner" is from 1590.
Blunt, street slang for "marijuana and tobacco cigar" (easier to pass around, easier to disguise, and the stimulant in the tobacco enhances the high from the pot) surfaced c.1993, but is said to have originated among Jamaicans in New York City in the early 1980s; from
Phillies Blunt brand cigars.
"Users say that the Phillies Blunt brand produces less harsh-tasting or sweeter smoke. The leaf wrapper of a Phillies Blunt is strong enough to hold together through the manipulations of making a blunt. Other brands fall apart."
[http://nepenthes.lycaeum.org/Drugs/THC/Smoke/blunts.html]