Lacking distinctive qualities or interesting features; bland, dull, and forgettable.
From character plus -less (suffix meaning 'without'). Originally meant 'without distinguishing marks or qualities.' The Greek root charaktēr combines with the Old English suffix -less.
A characterless person or place is literally someone or somewhere without 'character'—without the marks, quirks, or distinctive features that make things memorable. It's the opposite of having personality.
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