puzzle
An enigma is a puzzle, or a situation that is perplexing, inexplicable, or ambiguous. Synonyms can be puzzle, riddle, mystery, question, or conundrum.
A riddle for "glad" could be: "I am a feeling that lifts your spirits high, but not sad am I. What am I?" The answer would be "gladness," as it is a synonym for happiness or joy. Riddles often play on words and require critical thinking to solve.
That seems like more of a riddle(judging by the category, it is.). It might be "cool" ...It may be "calm"
Synonyms for a mystery are enigma, secret, puzzle, conundrum, riddle, or unknown.For a mystery novel, it could be a whodunit, suspense story, or thriller.
"The answer to my riddle" is not specific....Whose riddle? What riddle?
Taking out the word riddles makes this What is life if life isn't life but a life is a life yet life doesn't make sense like life should? This riddle makes no sense- a riddle is a riddle. a riddle is not, not a riddle because a riddle is a riddle. This riddle acts as if riddles are different than riddle (no s). To answer the riddle I would answer: Riddles are riddle.
the riddle is mogul
A quaint riddle is where the answer is in the riddle. There are many of riddles like this. A riddle that the answer is right in front of you is called is collection riddle. There are many of riddles that are like that.
life
An answer to a riddle.
Yes, it can be. For example, "He was seeking an answer for the riddle" (to the riddle).
A riddle that rhymes.