To convey the twin notions of nibbidaa being a state of
wisdom-produced revulsion and yet not a hate-rooted
affection, I know of no better word than "displacency".
Unfortunately, by the 19th century the meaning of this word
had changed to "incivility", and in the present degenerate
age it has become entirely obsolete.

Still, it might be worth reviving. For a delightful 18th
century example, see the opening paragraph of part II of Sir
Thomas Browne's _Christian Morals_ :

http://penelope.uchicago.edu/cmorals/cmorals2.html

Another possibility is "disrelish". This has an advantage
over displacency, in that it can also be used as a verb
(with "displacency" it's hard to know what to use for
nibbindati).

Best wishes,
Dhammanando Bhikkhu