'faultfinder' originates from English, a compound of 'fault' and 'finder', where 'fault' ultimately comes from Old French 'faute' (from Latin related to 'fallere' meaning 'to fail' or 'to deceive') and 'finder' comes from Old English 'findere' / 'findan' meaning 'to find'.

'fault' passed into Middle English from Old French 'faute' and Latin roots, while 'finder' derives from Old English 'findan'; the Modern English compound 'faultfinder' developed by combining these elements to mean 'one who finds faults'.

Initially the components referred to physical failings and the act of finding; over time the compound broadened to include both literal defect-finders (e.g., inspectors) and figurative faultfinders (habitual critics).