ra·tion·al·ize 
(răshə-nə-līz′)
(răshə-nə-līz′)v. ra·tion·al·ized, ra·tion·al·iz·ing, ra·tion·al·iz·es
v. tr.
1. To explain rationally: “Philosophy ... is essentially the endeavor of the human mind to rationalize the universe” (Francis E. Abbot).
2.
a. To attempt to justify (one's behavior) by providing reasons that obscure one's actual motives: rationalized cheating on his taxes as being a form of political protest.
b. To dismiss or minimize the significance of (something) by means of an explanation or excuse: “He could not rationalize the loss of some thirty thousand American lives in an unsuccessful war” (Robert Dallek).
3.
a. To make (a business or process, for example) more efficient, as by reducing costs or introducing modern methods.
b. To terminate the employment of (workers) in an effort to improve efficiency.
4. Mathematics To remove radicals, such as from a denominator, without changing the value of (an expression) or roots of (an equation).
v. intr.
1. To think in a rational or rationalistic way.
2. To rationalize one's behavior.
ration·al·iz′er n.