Lover girl describes a romantic, openly affectionate woman or girl who is into love. Sometimes self-applied: "I'm in my lover girl era." Not concerning. Often associated with Taylor Swift or similar artists. If your kid uses it constantly, ask them where they first heard it, not to police their speech but to understand which online community they are in. Most slang of this kind moves through TikTok and group chats, so seeing it in your child's vocabulary just means they are plugged into normal teen internet culture.