The meaning of realistic is of, relating to, or marked by literary or artistic realism : Let's be realistic (about this) - i just can't afford to pay that much money. It isn't realistic to expect people to work for so little money.
See examples of realistic used in a sentence. She gave us a realistic appraisal of our chances. If you are realistic about a situation, you recognize and accept its true nature and try to deal with it in a practical way.
A duck hunter skilled at making realistic decoys. There are four meanings listed in oed's entry for the adjective realistic, one of which is labelled obsolete. What you mean is, "in the real world, that is not going to happen." while you might really want to go to an ivy league college, it's probably more realistic to apply to state schools if your grades aren't that.
Definition of realistic adjective in oxford advanced learner's dictionary.