Adding unnecessary style flurishes to skilled activities, often beyond ones skill level, increasing the risk, and usually used to taunt or impress others.
That skateboarder was showboating to impress that girl when he broke his ankle.
"Wow Kara! when you stand to the side, i can only see your one glorious showboob, and not your smaller boob!" or "Oh my god. that girl's implants look so bad, at least she has a showboob."
A man or woman that takes joy In fucking in public places, usually in plain site. You'll most often see the Memphis Showboat in public parks, Jack Pirtle's Chicken parking lots, or Picadilley Cafeteria buffet lines.