The phrase "heft up" is commonly used to describe physically lifting something heavy or bulky. However, there are a variety of synonyms that can be used to convey the same idea. These include "hoist," "lift," "raise," "elevate," "uplift," and "boost." Additionally, more informal phrases such as "pick up," "grab," and "haul" can also be used to describe actions related to lifting. When writing, it's important to choose the synonym that best conveys the desired tone and context. By using these various alternatives to "heft up," you can effectively communicate the actions taking place within your writing.