The term 'billfish' refers to a group of predatory fish that have an elongated upper jaw, known as a bill. The most common species of billfish are marlins, sailfish, and swordfish. The crossword solution for the term 'billfish' is GAR, which is short for garfish, another species of billfish. Garfish are found in temperate and tropical waters around the world and have a long, slender body with a pointed snout.