The phrase "peg back" means to restrain or limit someone or something. There are a variety of synonyms that can be used in place of this phrase including, limit, restrict, confine, bridle, curtail, constrain, control, regulate, govern, tame, hold in check, rein in, pull in, and keep in check. Each of these alternatives is useful in different contexts, and some may be more appropriate than others depending on the situation. For example, "restrain" might be a more appropriate choice if the focus is on physical action, while "curtail" would be more appropriate if the focus is on reducing the amount of something.