Dry up is a common phrase used to express the act of something becoming dry, such as a stream, a pen, or a source of water. There are many synonyms for this phrase that might be used in different contexts. For example, desiccate is a synonym that might be used to describe the drying up of a fruit or a plant. Other synonyms might include parch, wither, dehydrate, shrivel, and wilt. Each of these words has a slightly different connotation, and the choice of which synonym to use will depend on the context and the desired effect on the reader or listener.