her mexican

It doesn’t mean anything. It’s just a load of old rubbish that someone asks you what it means without giving an answer and refuses to tell you because he/she doesn’t know what it means either.

Person: “Hey, do you know what ‘Her Mexican’ means?”
You: “What?”
Person: “Her Mexican”.
You: “No?”
Person: “Ha, you don’t know what it means, see ya!”
You: “?? Wft?”

Runster

Runster is a word that the beloved Hannah Barbara cartoon character “Scooby-Doo” pronounces the word “Monster”,

Scooby: “Raggy, RUNSTERS!!!!!!! RUNSTERS!!!!!!!!!

Shaggy: Oh no scoob!!!!!!!! (Screams)