A girl who ruins or attempts to ruin relationships, specifically by flirting with the boy of the relationship. A girl who is always involved and getting in the way of a relationship. Ami is seemingly sweet, but actually a back-stabbing person, might be beautiful on the outside, but is the absolute opposite on the inside.
"She's the Ami of that relationship."
"That girl keeps getting in the way of their relationship"
"Yeah she's the Ami of the relationship"