The Collaborative International Dictionary of English v.0.48:

Quasi \Qua"si\ [L.]
   As if; as though; as it were; in a manner sense or degree;
   having some resemblance to; qualified; -- used as an
   adjective, or a prefix with a noun or an adjective; as, a
   quasi contract, an implied contract, an obligation which has
   arisen from some act, as if from a contract; a quasi
   corporation, a body that has some, but not all, of the
   peculiar attributes of a corporation; a quasi argument, that
   which resembles, or is used as, an argument; quasi
   historical, apparently historical, seeming to be historical.
   [1913 Webster]

WordNet (r) 3.0 (2006):

quasi
    adj 1: having some resemblance; "a quasi success"; "a quasi
           contract"