The Collaborative International Dictionary of English v.0.48:

Intransient \In*tran"sient\, a.
   Not transient; remaining; permanent. --Killingbeck.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "intransient":
   abiding, age-long, aged, ancient, antique, chronic, constant,
   continuing, diuturnal, durable, enduring, evergreen, hardy,
   immutable, inveterate, lasting, long-lasting, long-lived,
   long-standing, long-term, longeval, longevous, macrobiotic,
   of long duration, of long standing, perdurable, perduring,
   perennial, permanent, perpetual, persistent, persisting, remaining,
   sempervirent, stable, staying, steadfast, tough, unfading, vital