aperio

Aperio, aperire, aperui, apertum, fourth conjugation. The participle does most of the heavy lifting: apertus, "open, uncovered, and of a person frank", and the standing phrase in aperto, "in the open".

Its opposite is operio, "cover over", and the two sit on the same root with ap- and op- in front, so a moment's inattention flips your sentence. Both senses of aperio run together without any sense of metaphor - it opens a door and it discloses a secret, and Latin does not feel a shift between them. The family gives English aperture, aperitif (the drink that opens the meal), and through Old French ouvrir, overt and overture.