[1] : The Collaborative International Dictionary of English v.0.48

unaccustomed \un`accus"tomed\, a.
   1. not used; not habituated; unfamiliar; unused; -- with to.
      1913 webster

            chastened as a bullock unaccustomed to the yoke.
                                                  --jer. xxxi.
                                                  18.
      1913 webster

   2. not usual; uncommon; strange; new.
      1913 webster

            what unaccustomed cause procures her hither? --shak.
      1913 webster

[2] : WordNet (r) 2.0

unaccustomed
     adj 1: not habituated to; unfamiliar with; "unaccustomed to wearing
            suits" ant: accustomed
     2: not customary or usual; "an unaccustomed pleasure"; "many
        varieties of unaccustomed foods"; "a new budget of
        unaccustomed austerity"
see also:
accustomed 

[3] : Moby Thesaurus II by Grady Ward, 1.0

50 moby thesaurus words for "unaccustomed":
   a novice at, a stranger to, callow, curious, disaccustomed, fresh,
   green, green as grass, ignorant, immature, inexperienced, new,
   new to, peculiar, rare, raw, rusty, strange, unaccustomed to,
   unacquainted with, unanticipated, uncommon, unconversant,
   unconversant with, undeveloped, unexpected, unexperienced,
   unfamiliar, unfamiliar with, unfledged, unhabituated, unhardened,
   uninitiated in, uninured, unmatured, unpracticed, unpracticed in,
   unprecedented, unripe, unseasoned, unskilled in, untrained,
   untried, unused, unused to, unusual, unversed, unversed in,
   unwonted, weaned

Unaccustomed >> U Words
Unaccustomed, definition of term: Unaccustomed
unaccustomed_pag1.html