rationalization has 3 distinct synonyms spread across 5 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
the cognitive process of making something seem consistent with or based on reason
(psychiatry) a defense mechanism by which your true motivation is concealed by explaining your actions and feelings in a way that is not threatening
Synonyms, antonyms and the broader and narrower relations for rationalization come from Princeton University’s WordNet. Full sources and licences.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
(mathematics) the simplification of an expression or equation by eliminating radicals without changing the value of the expression or the roots of the equation
the organization of a business according to scientific principles of management in order to increase efficiency
systematic organization; the act of organizing something according to a system or a rationale