A-alike is hip-hop slang for someone like-minded, particularly in gang contexts: "my a-alikes" = people who think like me. Not directly concerning but often used in gang-affiliated speech. 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.