When someone is a natural flirt and is mildly flirtacious with many, even though they don't have any romantic intent.
This tends to be mistaken for normal flirting, but it's in ones nature to make yourself seem as good a romantic partner to many, through our natural instincts, and is usually very subconcious.
Friend one: "You have a boyfriend, why are you flirting with that girl?"
Friend two: "I'm not, am I? I thought I was just being friendly."
Friend one: "Oh, you're just friendly flirting!"
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.