The phrase "run short" means to have an insufficient amount of something. There are several synonyms to express the same, such as "exhausted," "depleted," "low on," "scarce," "limited," "insufficient," "inadequate," "deficient," "scanty," "short of," "running out of," and "not enough." When a resource or time seems to be running out, always use one of these expressions instead of the commonly used phrase "run short." It will help you to express yourself more accurately and efficiently. Using the appropriate synonym helps the reader or listener to understand the message more clearly.