'assertible' is formed from the verb 'assert' plus the adjectival suffix '-ible' (from Latin '-ibilis'); 'assert' ultimately derives from Latin 'asserere'/'assertare'.

'assertible' developed by combining the Modern English verb 'assert' (from Old French/Latin roots) with the Latin-derived suffix '-ible'; the verb 'assert' itself evolved from Latin 'asserere' → Medieval Latin/Old French forms → Middle English 'assert'.

Originally related to the Latin verb meaning 'to claim or affirm', the term evolved into an adjective meaning 'able to be asserted' in Modern English.