'misunderstander' originates from English, formed from the negative prefix 'mis-' (from Old English 'mis-' meaning 'wrongly' or 'badly'), the verb 'understand' (from Old English 'understandan' meaning 'to comprehend'), and the agentive suffix '-er' (from Old English '-ere').

'understand' comes from Old English 'understandan'; the prefix 'mis-' was combined with 'understand' to form 'misunderstand' in Middle/Modern English, and the agentive suffix '-er' was later attached to produce the derived noun 'misunderstander' in Modern English usage.

The original elements meant 'wrongly' + 'to comprehend', and over time the combined form came to mean specifically 'one who misunderstands' rather than any broader sense.