first impression

noun2

1. •
   The event when one person first encounters another person and forms a mental image of them. ᵂᵖ

   • I obviously didn't make much of a first impression with him, because he didn't recognize me from the party two weeks ago.
2. •
   (of a case, issue, etc.) The state of not having been previously raised within a particular jurisdiction. ᵂᵖ

   • Because the law was just recently passed, this is a case of first impression.