How about a conundrum? Or an enigma.
Enigma most nearly means puzzle or riddle.
His disappearance is an enigma that has given rise to speculation
Enigma means: mystery: somebody or something that is not easily explained or understood.So the antonym would probably be something like the solution to a problem.
An enigma is a puzzle, or a situation that is perplexing, inexplicable, or ambiguous. Synonyms can be puzzle, riddle, mystery, question, or conundrum.
The use of the word enigma is apparently an enigma to you! Delicious irony!
The Enigma goes by Slug.
"An enigma wrapped in mystery and riddled with controversy" is how UFO's have been described. He/she is an enigma. The location of 'The Lost Dutchman' gold mine remains an enigma.
El código Enigma in Spanish is "the Enigma code" in English.
Enigma Motorsport was created in 2008.
Enigma of the Hour was created in 1911.
Enigma Titanium was created in 2005.
The Pernicious Enigma was created in 1997.
Enigma - novel - was created in 1995.
Enigma Records ended in 1989.
The ISBN of The Great Enigma is 9100103101.
Enigma Records was created in 1980.