The term PLAYFUL SWIMMER can be broken down into two crossword solutions: OTTER (5 letters) and RIVEROTTER (10 letters). Otters are a type of mammal that live in both marine and freshwater habitats. They are known for their playful behavior, which includes sliding down muddy banks, chasing each other, and playing with objects. River otters are a species of otter that live in rivers and streams and are also known for their playful behavior.