10 letters · 18 points in Scrabble
noun a stupid foolish person
originUncertain; the first element nincom- is possibly from the name Nicholas or Nicodemus (compare French nicodème (“foolish or gullible person”), from the Pharisee named Nicodemus mentioned in the Bible who asks Jesus seemingly naive questions: see John 3:1–21), or from ninny (“foolish or silly person”), while the second element -poop could be derived from poop (“(obsolete) to cheat, deceive, fool”).…
Etymology from Wiktionary, CC BY-SA 3.0