'uneven-legged' originates from English, formed as a compound of 'uneven' and 'legged', where the prefix 'un-' meant 'not' and 'even' meant 'level', and 'legged' derives from 'leg' with the adjectival '-ed' meaning 'having legs'.

'uneven' itself comes from Old English/Proto-Germanic roots for 'even/level' combined with the negative prefix 'un-' from Old English 'un-', while 'legged' is built from Old English 'lēg'/'leg' plus the adjective-forming suffix '-ed'; the components combined in Modern English to form the descriptive compound 'uneven-legged'.

Originally the components meant 'not level' (uneven) and 'having legs' (legged); over time the compound came to specify the more focused meaning 'having legs of unequal length' or 'having legs that cause instability'.