What the dictionary says impression means:
1. A strong effect made on the understanding, feelings, conscience, etc. 2. The first and instant effect of an experience; sensation. 3. The effect made from an organization or influence.4. A belief of a indefinite nature5. A mark produced by pressure.
What I think impression means:
The judgment you immediately make upon someone you don't know or have very little knowledge of.
Impression is a noun.
When I first walked in the door, all eyes immediately look my way, judging my every move, making impressions just based upon the way that I walk.