n.
   - chiefly N. Amer. a tall cupboard or wardrobe.
 - a small room. 
▸archaic a toilet.
 - 
(the closet)
 (especially with reference to homosexuality) a state of secrecy or concealment. 
▸
[
as modifier]
 secret; covert:
 a closet socialist.
 
v.
 (closets, closeting, closeted)
  - shut away in private conference or study:
 he was closeted with the king.
 - 
[as adj. closeted]
 keeping something, especially one's homosexuality, secret.
 
 
  Etymology
  ME: from OFr., dimin. of clos (see close1).