1) Difficult 2) Disowned 3) Repudiated 4) Unconfessed 5) Undeclared 6) Unknown 7) Unrecognized 8) Unvalued 1) Disowned 2) Not openly acknowledged 3) Not recognized or admitted 4) Repudiated 5) Secret 6) Unappreciated 7) Unavowed 8) Unconfessed 9) Unknown 10) Unrecognised 11) Unrecognized 12) Unsung 13) Unvalued 
[adj] - not openly acknowledged 2. [adj] - not recognized or admitted
adjective not openly acknowledged; `an unacknowledged emergency`