Mur
1. a word with the most vague definition - it can be defined as anything. circumstances under which this word is often used is when it is needed to replace another word that shouldn't be uttered, or has been temporarily forgotten. a synonym for the words "thing," "stuff," etc.

A: "Hey, let's smoke some mur."
B: "You go ahead, I'm already really fucking stoned."

1 1/2. marijuana

2. a word used to fill a silence...particularly helpful for the socially awkward, misunderstood and nonchalant person
A: "Mur."
B: "What?"
A: "I'm awkward."