The expression of frustration, disbelief or irritation occurs through GMFU. As an example, one may say, I got him walking in the rain-GMFU, in which case he/she feels irritated or abused. It may also be applied in a joking form such as; I believed the test was going to be simple, but that test GMFU. The slang provides emotional intensity to the message in most instances. Due to the profanity, it is normally taken as an informal conversation when one is privately talking with friends who will know the tone of the conversation. Know more about what does gmfu mean