'pettishness' originates from English, formed by adding the suffix '-ness' to the adjective 'pettish'.

'pettish' developed in English from forms related to 'petty' (Middle English 'petit/petty'), ultimately from Old French 'petit' meaning 'small, little'; the suffix '-ness' was then added to make the abstract noun 'pettishness'.

Initially associated with the idea of being 'small' or 'trivial' (from 'petty'), the sense shifted to 'easily annoyed or peevish'; 'pettishness' now means that state of irritability or sulkiness.