bothersome (adj.)

1718, also bauther, bather, bodder, "to bewilder, confuse;" 1745 as "give trouble to;" first in Irish writers (Sheridan, Swift, Sterne), hence probably from Anglo-Irish pother, which is perhaps from Irish bodhairim "I deafen." Related: Bothered; bothering. As a noun from 1803.

word-forming element used in making adjectives from nouns or adjectives (and sometimes verbs) and meaning "tending to; causing; to a considerable degree," from Old English -sum, identical with some, from PIE root *sem- (1) "one; as one, together with." Cognate with Old Frisian -sum, German -sam, Old Norse -samr; also related to same.

"It usually indicates the possession of a considerable degree of the quality named: as mettlesome, full of mettle or spirit; gladsome, very glad or joyous" [Century Dictionary]. It is also, disguised, the ending in buxom. For the -some used with numbers (twosome, foursome, etc.), see -some (2).