Pleskun (read it with long "u") is something like "Slap-man". It came from Czech Republic and it means swear-word, but not so strong- just like dummy or something.
"You are pleskun!"
Came from Czech Republic and it means "The one who steps on his testicles while walking."
"Wow! That´s Vajcoslap!" He said, when discoverd alien with testicles on his feet