'impishness' originates from English, specifically the adjective 'impish', where the root 'imp' goes back to Old English 'impa' meaning 'a young shoot' or 'graft'.

'impishness' developed from the adjective 'impish' (formed from 'imp'), with 'imp' originally referring to a 'young shoot' in Old English 'impa'; by the 16th century 'imp' had acquired the sense 'small mischievous being (demon)', and 'impish' came to mean 'mischievous', leading to the noun 'impishness' (impish + -ness).

Initially, 'imp' meant 'a young shoot' or 'graft', but over time the sense shifted to a 'small mischievous creature' and then to human qualities of 'mischievousness'; consequently 'impishness' now means 'playful mischief' or 'mischievousness'.