Wassies are tiny creatures with room temperature IQ. They are usually a mix of platypuses, frogs, ducks, or penguins and the result of radioactive incidents or mysterious apocalyptic events. Their short lifespan extends further if kept in a fridge after which they respawn with the knowledge of their ancestors.
Some people derive amusement from targeting them, while others passionately stand up to their defense but wassies simply cannot be stopped or eradicated.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
British slang for a scientist or technical expert, esp . when the speaker is not certain of the expert’s specific field of study. Not necessarily derogatory, but typically used by persons without a technical background. In the US, the equivalent would be “egghead”, “squint”, or “geek.”
Origin of the word is unknown. Started sometime in World War 2. Given the typical evolution of British slang, could easily have started because what these experts did was confusing or “baffling” to the common person.