transitive verb rationalized -·ized′, rationalizing -·iz′·ing

1. to make rational; make conform to reason
2. to explain or interpret on rational grounds
3. Chiefly Brit. to apply modern methods of efficiency to (an industry, agriculture, etc.)
4. Math. to remove the radical signs from (an expression) without changing the value
5. Psychol. to devise superficially rational, or plausible, explanations or excuses for (one's acts, beliefs, desires, etc.), usually without being aware that these are not the real motives

intransitive verb

1. to think in a rational or rationalistic manner
2. to rationalize one's acts, beliefs, etc.