The term 'CROW's-Nest Supporter' refers to a person who is responsible for providing support to the CROW's nest, which is a lookout station on a ship. This person is typically responsible for ensuring that the lookout station is properly maintained and that the crew members in the CROW's nest are able to perform their duties safely and effectively. The job of a CROW's-Nest Supporter can be fulfilled by someone with the four-letter word 'MAST', which is short for 'MASTER'.