A word used to describe the teasing and pisstaking which occurs between mates, usually harmless.
However, the past couple of years the word has been hijacked by Justin Bieber lookalike student "LAD" twats who use it to describe anything humorous that occurs. These people are also known as chino wankers, annoying morons and people who need to use a dictionary now and again.
What banter is:
"You alright Mike? You seem miles away, you're not busy thinking of Tanya are you? Don't even lie, you proper fancy her, you div!"
What banter isn't:
"LOL LAST NIGHT DAVE WALKED INTO A LAMPPOST! EPIC BANTER LOL! WHAT A LAD!"