"Negative entropy" seems fine for the purpose. It has a clear meaning which is relevant to the phenomenon under consideration, and it's doubtful that anyone will read more into the expression than is intended.
Some people do like to sew a coat onto a button.
Negative entropy (informational, not thermodynamic) is just a measure of how many messages can be carried by a system. "Information" (in the sense of Prisoner Number Six) is an arbitrary. Messages may have any "meaning" although the number of these meanings is limited by the entropy.