"Well, now, that depends. Some of them you can understand just by looking at a person, some of them follow directly from some incident or another, others make no real sense at all unless you understand the mind of the person who started it. Our Radar got his on account of his uncanny hearing, but I've known others named things like Soap, or Blister, or so on, so forth."

She gestures loosely, leaving the unfavourable stories or personality traits that could lead to those up to the imagination.

"Generally speaking the more impressive the nickname, the more ridiculous or terrible the story behind it. I knew once of a 'Bullseye' who was known for... let's say his virility."

That's a somewhat more polite way to say 'kept having illegitimate children through one night stands'.