OVERTLY OPEN

Today, the word overt refers to something done in a transparent manner, but in Middle English, it had more literal definitions of "open" or "uncovered". The adjective is borrowed from Middle French ouvert - which is still extant in Modern French as meaning "open" - and that comes from Old French uvert and Latin aperire, a verb for "open" that is also the source of words like overture, aperture, and aperitif. Finally, that derives from Proto-Italic hepo and the Proto-Indo-European reconstruction hwer, meaning "to cover" or "shut" (this turned into its antonym through a connotation of "uncover". Descendants include discover,  curfew, garage, warrant, guarantee, and more). According to Google NGrams, usage of the word overt peaked in 1974 and has been on a steady decline since then.