Rationalize is to attempt to justify something or to make excuses for bad behavior or an unpleasant outcome.(verb)
When you steal from your friends but justify it based on the theory that they are spoiled and won't notice the money is gone, this is an example of a situation where you rationalize your behavior.
See rationalize in Webster's New World College Dictionary
See rationalize in American Heritage Dictionary 4
verb ra·tion·al·ized, ra·tion·al·iz·ing, ra·tion·al·iz·es verb, transitive
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