'duckish' originates from English, specifically formed from the noun 'duck' + the suffix '-ish', where 'duck' ultimately came from Old English 'dūce' meaning 'diver' (from the verb 'dūcan' to duck) and the suffix '-ish' meant 'having the quality of'.

'duck' changed from Old English 'dūce' (from the verb 'dūcan') and later the Old English adjectival suffix '-isc' (modern '-ish') was added to form adjectives; through Middle English this produced adjectives like 'duckish' meaning 'of or like a duck'.

Initially it meant 'of or pertaining to a duck' (literally like a duck); over time the primary meaning has remained but figurative senses (e.g., 'waddling, awkward') have developed.