Source : Webster's Revised Unabridged Dictionary (1913)

Secretly \Se"cret*ly\, adv.
   In a secret manner.

Source : WordNet®

secretly
     adv 1: in secrecy; not openly; "met secretly to discuss the
            invasion plans"; "the children secretly went to the
            movies when they were supposed to be at the library";
            "they arranged to meet in secret" [syn: {in secret}, {on
            the Q.T.}, {on the QT}]
     2: not openly; inwardly; "they were secretly delighted at his
        embarrassment"; "hoped secretly she would change her mind"