The word Naktiv comes from the combination of NAKed and acTIVe, and is inspired by the Gramer's fine Nacktiv activities. The original concept being to bring non-sexual nakedness into ones daily life.
Different languages will have different variations. Which version one uses is much like the debate between the terms nudist and naturist.
All of these terms are just labels, and sometimes useful, to use when they make sense.