covert
adjective
• not openly acknowledged or displayed.
• "covert operations against the dictatorship"
Similar:
secret,
furtive,
clandestine,
surreptitious,
stealthy,
cloak-and-dagger,
hole-and-corner,
hole-in-the-corner,
closet,
behind-the-scenes,
backstairs,
back-alley,
under-the-table,
hugger-mugger,
concealed,
hidden,
private,
sly,
sneaky,
underhand,
undercover,
underground,
black,
hush-hush,
covert
noun
• a thicket in which game can hide.
• a feather covering the base of a main flight or tail feather of a bird.
• a flock of coots.
• "it is a good omen when a covert of coots have taken to any particular locality"
Origin:
Middle English (in the general senses ‘covered’ and ‘a cover’): from Old French, ‘covered’, past participle of covrir (see cover).
