naked truth

Plain unadorned facts, without concealment or embellishment. For example, What I've told you is the naked truth. This expression supposedly alludes to a fable in which Truth and Falsehood went bathing, Falsehood then dressed in Truth's clothes, and Truth, refusing to take another's clothes, went naked. [Late 1500s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.