Dewott is a bipedal, otter-like Pokémon that is primarily light blue. It has small black ears, a pointed crest at the back of its head, a red nose, and long white whiskers forming tilted V-shapes. Two pointed teeth are visible in the upper jaw when its mouth is open. Its forelimbs have three fingers on each black paw. Its feet and flat tail are black. Around its waist is a large, dark blue, fringed arrangement of fur, with two scalchops on the thighs. These scalchops are detachable, and Dewott trains to use several techniques with them.
Dewott may be a combination of dew, water, and otter. It may also involve duel or dual (referring to the two scalchops it fights with), or duo (Italian for two, referring to its place in its evolutionary line). Notably, Helen DeWitt is the name of the author of The Last Samurai.
Futachimaru may be a combination of 二つ futatsu (two), 太刀 tachi (long sword), and 丸 maru (a common ending in a boy's name, especially in the time of samurai). 二 futa (alternate reading of ni) may refer to Dewott's place in the evolutionary line.