The phrase "stuffed to the gunwales" is typically used to describe something that is completely full or overflowing. Some potential synonyms for this phrase include "packed to capacity," "brimming," "bursting at the seams," "crammed," "chock-full," and "teeming." These words all emphasize the idea that something is full, whether it's a physical space, a container, or a person's schedule. Other similar phrases might include "full to the gills," "stuffed to overflowing," or "stuffed to the rafters." Regardless of the wording, the message remains the same; when something is stuffed to the gunwales, there's no room for anything else.