What is the meaning of rationalize?

verb

• Defend, explain, clear away, or make excuses for by reasoning.
  • usage: "rationalize the child's seemingly crazy behavior"; "he rationalized his lack of success"
  • synonyms: apologize, apologise, excuse, justify, rationalise
• Weed out unwanted or unnecessary things.
  • usage: "We had to lose weight, so we cut the sugar from our diet"
  • synonyms: cut, prune, rationalise
• Structure and run according to rational or scientific principles in order to achieve desired results.
  • usage: "We rationalized the factory's production and raised profits"
  • synonyms: rationalise
• Think rationally; employ logic or reason.
  • usage: "When one wonders why one is doing certain things, one should rationalize"
  • synonyms: rationalise
• Remove irrational quantities from.
  • usage: "This function can be rationalized"
  • synonyms: rationalise