1. increase or reduce smth. by fifty percent of the original amount:
- This move cuts by half the religious programming on ITV on Sunday.
2. far more than is satisfactory or desirable:
- Of course, he is a very clever politician. Too clever by half, in my opinion.
by halves—do smth. imperfectly or not completely:
- Those in charge should not deal by halves with a question in which all classes have so deep an interest.