The principal cause of disturbance or disruption; someone who most greatly upsets peace or stability.
From 'arch-' (chief, principal) combined with 'disturber' (one who disturbs), derived from Old French 'disturber' (to throw into disorder). This is a rare, literary term appearing primarily in formal or archaic prose.
This word barely survives in modern English, but when you see it in old texts, it's usually describing someone blamed for major social upheaval—it's the vocabulary of blame that assigns supreme responsibility for chaos.
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