Annoyed, troubled, or bothered intensely; vexed.
From 'be-' plus 'bothered' (past participle of 'bother,' origin uncertain but possibly imitative). The 'be-' prefix intensifies the sense of being troubled.
Southern American English kept versions of this—'flustered and bebothered' sounds like something from a 1960s sitcom, showing how these 'be-' words lasted longer in casual speech than formal writing.
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