(TMZ) -- A 'Jeopardy' contestant learned the hard way that Alex Trebek and co. are sticklers when it comes to pronunciation ... especially between "gangster" and "gangsta."
Nick Spicher appeared on the trivia show Monday night, where he was asked to provide the question to a clue that included Coolio's song "Gangsta's Paradise" and author John Milton's book "Paradise Lost."
His answer -- "Gangster's Paradise Lost" -- was almost correct ... except he said -ster instead of -sta. He was awarded $1,600 at first, but Trebek circled back and deducted the money when judges found his answer to be inaccurate, taking away an additional $1,600.
What is ... damn you, Coolio!