unaccustomed

/ˈʌnəˌkʌstəmd/

Other forms: unaccustomedly

If you're unaccustomed to something, you're not used to it. When you're unaccustomed to riding a horse, it might take a while to get the hang of staying in the saddle.

An unaccustomed knock on the door might startle you and make your dog bark in alarm, and an unaccustomed bonus in your paycheck will come as a happy surprise. You might feel awkward having tea with a princess in a palace if you're unaccustomed to fine dining and dignified table manners. The prefix un here means "not," and it's combined with accustom, with its ultimate Latin root word consuetudinem, "habit, usage, practice, or custom."

Definitions of unaccustomed

1. adjective

   not habituated to; unfamiliar with
   “unaccustomed to wearing suits”

   synonyms:

   new

   unfamiliar

   unused

   infrequently exposed to

   antonyms:

   accustomed

   (often followed by `to') in the habit of or adapted to

   used to, wont to

   in the habit
2. adjective

   not customary or usual
   “an unaccustomed pleasure”

   “many varieties of unaccustomed foods”

   “a new budget of unaccustomed austerity”

   synonyms:

   unusual

   not usual or common or ordinary