Having a brain like a sieve, can you solve it? (6)
I believe the answer is:
riddle
If this is the answer, I'm afraid I cannot explain it.
Can you help me to learn more?
(Other definitions for riddle that I've seen before include "Cryptic question" , "Question to test ingenuity, something puzzling" , "Difficult problem or coarse sieve" , "Make many openings" , "Cryptic verse" .)