The term "full boards" traditionally refers to the concept of something being completely occupied or fully booked. However, there are several synonyms that can be used to convey the same meaning. For instance, the term "fully loaded" or "completely packed" can be used to describe a space that is fully occupied. Another synonym is "at capacity" which implies that the space or resource is filled to its maximum limit. Additionally, the phrase "at full occupancy" or "booked up" can also be used to describe a situation where every available space or resource is fully utilized. In conclusion, there are several alternatives to the phrase "full boards" for communicating the idea of complete occupancy or booking.