The Collaborative International Dictionary of English v.0.48:

Reversionary \Re*ver"sion*a*ry\, a. (Law)
   Of or pertaining to a reversion; involving a reversion; to be
   enjoyed in succession, or after the termination of a
   particular estate; as, a reversionary interest or right.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Reversionary \Re*ver"sion*a*ry\, n. (Law)
   That which is to be received in reversion.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reversionary
    adj 1: of or relating to or involving a reversion (especially a
           legal reversion); "reversionary annuity"; "reversionary
           interest"

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "reversionary":
   atavistic, compensatory, indemnificatory, reactionary, recessive,
   recidivist, recidivous, redeeming, redemptional, redemptive,
   regressive, reparative, restitutive, restitutory, restorative,
   retributive, retrograde, retrogressive, retrorse, retroverse,
   returnable, reversible, reversional, revertible, revulsionary