The Collaborative International Dictionary of English v.0.48:

Unfeeling \Un*feel"ing\, a.
   1. Destitute of feeling; void of sensibility; insensible;
      insensate.
      [1913 Webster]

   2. Without kind feelings; cruel; hard-hearted.
      [1913 Webster]

            To each his sufferings: all are men,
            Condemned alike to groan;
            The tender for another's pain,
            Th' unfeeling for his own.            --Gray.
      [1913 Webster] -- Un*feel"ing*ly, adv. --
      Un*feel"ing*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

unfeelingly
    adv 1: without compassionate feelings; "unfeelingly, she
           required her maid to work on Christmas Day" [ant:
           feelingly]
    2: in a callous way; "he callously exploited their feelings"
       [syn: callously, unfeelingly]