Concealed, a.
Hidden; kept from sight; secreted. -- Con*ceal"ed*ly (, adv. -- Con*ceal"ed*ness, n. Concealed weapons (Law), dangerous weapons so carried on the person as to be knowingly or willfully concealed from sight, -- a practice forbidden by statute.
Shades of meaning
Fernald lists concealed only as an antonym, under evident.
Where he writes about it:
A house is hidden by foliage; the bird's nest is artfully concealed. — from hide
Whatever is buried is hidden or concealed; but there are many ways of hiding or concealing a thing without burying it. — from hide
Synonyms
none given