'dotard' originates from Middle English, specifically the word 'dotard', where the root 'dote' meant 'to be foolish' or 'to show mental decline' and the suffix '-ard' was a pejorative formation meaning 'person characterized by'.

'dotard' developed from Middle English 'dotard', itself formed from the verb 'dote' (Middle English 'doten') plus the suffix '-ard'; the verb 'dote' goes back to earlier Germanic/Old English forms meaning 'to act foolishly', and over time the compound stabilized as the modern English 'dotard'.

Initially it meant 'a person given to doting or foolishness', but over time it evolved into the current meaning of 'an old person showing mental decline' and is now chiefly used as a pejorative term.