stumper

Plural: stumpers

Noun

• A difficult or baffling question; a challenging problem.
• a particularly difficult or baffling question or problem
• One who stumps, or speaks, or orates, as a politician.
• A wicketkeeper.
• A difficult puzzle or problem.
• A boastful person.

Examples

• Global warming is a real stumper.
• He's not yet well known, but he's a good stumper.
• That seven-letter word on a triple-word score was a real stumper, but he found it.

Synonyms

poser, sticker, toughie, puzzler