'testableness' originates from English, specifically formed by adding the noun-forming suffix '-ness' to the adjective 'testable' (itself from the verb 'test' + the adjectival suffix '-able').

'testable' derived from the verb 'test' + '-able'; the verb 'test' in the sense 'to examine or try' is post-classical English ultimately influenced by Old French 'test' (used in assaying) and Latin 'testa' (earthen pot used in assaying). The abstract noun 'testableness' is a modern English formation built from 'testable' + '-ness'.

Initially the components conveyed 'able to be put to a test' and this has remained, though modern usage often emphasizes empirical verifiability or falsifiability.