stumper

1. One who stumps, or speaks, or orates, as a politician.

2. (разговорное)A wicketkeeper.

   He's not yet well known, but he's a good stumper.

3. (разговорное)A difficult puzzle or problem.

   Global warming is a real stumper.

   a particularly difficult or baffling question or problem

4. (архаичное, сленг)A boastful person

правильный