Code:
[05:11 PM Sat May 31: root @ /home/stephen]
># apt-cache policy kdict
kdict:
  Installed: (none)
  Candidate: 4:2.2.2-14.1
  Version Table:
     4:3.1.2-1 0
        500 http://ftp.de.debian.org unstable/main Packages
     4:2.2.2-14.6 0
        500 http://security.debian.org stable/updates/main Packages
     4:2.2.2-14.1 0
        990 http://ftp.de.debian.org testing/main Packages
     4:2.2.2-14 0
        500 http://ftp.de.debian.org stable/main Packages
[05:12 PM Sat May 31: root @ /home/stephen]
># apt-get -s install kdict/unstable
Reading Package Lists... Done
Building Dependency Tree... Done
Selected version 4:3.1.2-1 (Debian:unstable) for kdict
The following NEW packages will be installed:
  kdict
0 packages upgraded, 1 newly installed, 0 to remove and 33  not upgraded.
Inst kdict (4:3.1.2-1 Debian:unstable)
Conf kdict (4:3.1.2-1 Debian:unstable)
I think you would be better off just installing the single package. But if you are on a high speed connection and can do without the 12 packages that will be removed it looks like it's going to work properly.