The Collaborative International Dictionary
Under \Un"der\, a. Lower in position, intensity, rank, or degree; subject; subordinate; -- generally in composition with a noun, and written with or without the hyphen; as, an undercurrent; undertone; underdose; under-garment; underofficer; undersheriff.
Under covert (Zo["o]l.), one of the feathers situated beneath the bases of the quills in the wings and tail of a bird. See Illust. under Bird.
Usage examples of "under covert".
All the government offices are under covert surveillance by plain -- clothes peeps and as soon as I got here I shut down the only two safe -- houses we had because they were no longer safe.
Now here's how we go about it: as of tonight the Sanderson girl goes under covert surveillance.
Conway had been planning simply to keep them under covert but close observation here, and then have his men take them on their way out - as many of them as he could get without raising a disturbance.
This was the same feeling that had gripped him in the inn at the start of this whole wide adventure, that be was under covert observation.
He who had had to subsist on mere fugitive glances, looks winged in flight and swiftly lost under covert, now found her eyes settling on him with a brooding intensity that fairly dazzled him.