'toothless' originates from Old English, specifically the word 'tōþ' for 'tooth' and the suffix '-lēas' meaning 'without'.

'toothless' changed from the Old English compound 'tōþlēs' (tōþ + -lēs) and eventually became the modern English word 'toothless' through Middle English developments.

Initially, it meant 'without teeth' in a strictly literal sense, but over time it also evolved to mean 'lacking force or effectiveness' in a figurative sense.