The Collaborative International Dictionary of English v.0.48:

Sacrosanct \Sac"ro*sanct\, a. [L. sucrosanctus.]
   Sacred; inviolable. [R.] --Dr. H. More.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sacrosanct
    adj 1: must be kept sacred [syn: inviolable, inviolate,
           sacrosanct]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "sacrosanct":
   awesome, awful, divine, esteemed, heavenly, holy, ineffable,
   inenarrable, inexpressible, inviolable, inviolate, numinous,
   regarded, religious, respected, sacred, spiritual, unspeakable,
   untouchable, unutterable, venerable