形容词

1. 不习惯的；不熟悉的；不适应的
If you are unaccustomed to something, you do not know it very well or have not experienced it very often.

2. 不寻常的；奇怪的
If you describe someone's behaviour or experiences as unaccustomed, you mean that they do not usually behave like this or have experiences of this kind.

1. not habituated to
unfamiliar with

e.g. unaccustomed to wearing suits

2. not customary or usual

e.g. an unaccustomed pleasure
many varieties of unaccustomed foods
a new budget of unaccustomed austerity