Secret, surreptitious, concealed.
Under coverture.
A covering.
A disguise.
A feather that covers the bases of flight feathers.
Area of thick undergrowth where animals hide.
A hiding place.
Of a thing: done with evasive or guilty secrecy.
Of a thing: that has been acquired by theft; stolen; also (generally) taken stealthily.
Of a person or an animal: sly, stealthy.
Of a person, etc.: inclined to steal; pilfering, thieving.