Vincent's NT Word Studies
3. If so be (ei ge). Assuming that.Being clothed. Compare Job x. 11.
Naked (gumnoi). Without a body. The word was used by Greek writers of disembodied spirits. See the quotation from Plato's "Gorgias" in note on Luke xii. 20; also "Cratylus," 403, where, speaking of Pluto, Socrates says: "The foolish fears which people have of him, such as the fear of being always with him after death, and of the soul denuded (gumnh) of the body going to him." Stanley cites Herodotus' story of Melissa, the Corinthian queen, who appeared to her husband after death, entreating him to burn dresses for her as a covering for her disembodied spirit (v., 92). The whole expression, being clothed - naked is equivalent to we shall not be found naked because we shall be clothed.
Robertson's NT Word Studies
5:3 {Being clothed} (endusamenoi). First aorist middle participle, having put on the garment. {Naked} (gumnoi). That is, disembodied spirits, "like the souls in Sheol, without form, and void of all power of activity" (Plummer).