You searched for: “contronym
contranym, contronym (s) (noun); contranyms, contronyms (pl)
1. Any word which can be its own counter application.
2. A word that generates two opposite meanings.

More popularly, they are known as Janus-faced words because the Greek god Janus had two faces which looked in opposite directions.

"The moon is visible tonight."
"The lights in the old house are always invisible."

Although the two italicized words are opposite in meaning, both can be replaced by the same word out. When the moon or sun or stars are out, they are visible; and when the lights are out, they are invisible; therefore, out is considered a contronym.

—"Naming the nyms", by Richard Lederer (from http://wordsmith.org/awad; December 14, 2001).

An additional example includes: "cleave", meaning "adhere" and "separate".