'projectiveness' originates from Latin, specifically the verb 'proicere' (later classical form 'proicĕre'), where the prefix 'pro-' meant 'forward' and the root related to 'jacere/jicere' meant 'to throw'.

'projectiveness' developed via the adjective 'projective' (from Late Latin 'projectivus' and Medieval/Modern Latin usage), adopted into English as 'projective' and later nominalized to form 'projectiveness'.

Initially related to the literal sense 'to throw forward,' it evolved through figurative senses ('to put forward, present') into the abstract sense 'having the quality of projecting' used in modern English (including technical senses in mathematics and psychology).