ADJECTIVE (2)

1. not habituated to; unfamiliar with;
- Example: "unaccustomed to wearing suits"

2. not customary or usual;
- Example: "an unaccustomed pleasure"
- Example: "many varieties of unaccustomed foods"
- Example: "a new budget of unaccustomed austerity"

The Collaborative International Dictionary of English v.0.48:

Unaccustomed \Un`ac*cus"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]

WordNet (r) 3.0 (2006):

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"