The word 'truthiness' is a modern coinage, popularized in the 21st century, which deliberately applies a traditional English morphological pattern to a contemporary concept. It is constructed from the native English word 'truth', which itself evolved from the Old English trēowth, a derivative of trēowe (faithful, true), ultimately from a Proto-Germanic root related to steadfastness and trust. The suffix '-ness', of Germanic origin, is one of the most common and productive means of forming abstract nouns denoting a state or quality in English. The term's logic is intentionally transparent and ironic: it uses the established, authoritative machinery of English word formation ('truth' + '-ness') to name the quality of something that merely has the feel of truth, rather than its substance, thus highlighting the tension between perception and reality.

Structure: truth (true) + i (connective) + ness (noun suffix) - truth: From Old English trēowth, meaning 'faithfulness, constancy'. In this compound, it carries the sense of 'conformity to fact'. - i: A connective vowel, often used in English to join a root ending in a consonant to a suffix beginning with one. - ness: A noun-forming suffix from Old English -nes(s), used to denote a state, quality, or condition.