covert
n. B2 Upper Intermediate US //ˈkoʊvɝt// UK //kəʊvˈɜːt// covert
n. done in secret or hidden from others. You use this word when an action is not open or obvious.
n. done in secret or hidden from view; not openly acknowledged or displayed.
The spy ran a covert operation.
The government launched a covert mission to gather intelligence.
Behind the scenes, the agency maintained a covert network of informants.
From Middle English covert, from Old French covert, past participle of covrir (“to cover”) (corresponding to Latin coopertus); cognate to cover. Not closely related to overt, despite what the most common pronunciation would suggest.