dull
adj.
c.1200, "stupid;" early 13c., "blunt, not sharp;" rare before mid-14c., apparently from Old English dol "dull-witted, foolish," or an unrecorded parallel word, or from Middle Low German dul "slow-witted," both from Proto-Germanic *dulaz (cognates: Old Frisian and Old Saxon dol "foolish," Old High German tol, German toll "mad, wild," Gothic dwals "foolish"), from PIE *dheu- (1) "dust, vapor, smoke" (and related notions of "defective perception or wits"). Of color from early 15c.; of pain or other sensations from 1725. Sense of "boring" first recorded 1580s.
dull. (8) Not exhilarating; not delightful; as to make dictionaries is dull work. [Johnson]
Dullsville, slang for "town where nothing happens," attested from 1960.v.
c.1200, "to grow weary, tire;" of pointed or edged things from c.1400; of the senses from 1550s; from dull, adj.. Related: Dulled; dulling.