'disquiet' originates from Latin and Old French, specifically from the Latin prefix 'dis-' meaning 'not' or 'apart' and the Latin word 'quietus' meaning 'rest' or 'quiet', transmitted via Old French.

'disquiet' changed from Old French/Anglo-Norman forms (for example Old French 'desquieter' or Anglo-French 'desquieter') and Middle English 'disquieten' and eventually became the modern English word 'disquiet'.

Initially, it meant 'to deprive of rest or quiet' (i.e., to disturb calm); over time it evolved into the current sense 'to make anxious or uneasy' and the related noun sense 'a feeling of unease'.