The DICT Development Group

  exposit \exposit\ v.
     1. to set forth reasons; to explain or expound.
        [WordNet 1.5]
  
     2. to make external.
  
     Syn: externalize, externalise.
          [WordNet 1.5]

  exposit
      v 1: state; "set forth one's reasons" [syn: set forth,
           expound, exposit]
      2: add details, as to an account or idea; clarify the meaning of
         and discourse in a learned way, usually in writing; "She
         elaborated on the main ideas in her dissertation" [syn:
         elaborate, lucubrate, expatiate, exposit, enlarge,
         flesh out, expand, expound, dilate] [ant:
         abbreviate, abridge, contract, cut, foreshorten,
         reduce, shorten]