Check riddle again? (8)
I believe the answer is:
restrain
'check' is the definition.
(restraining is a kind of checking)
'riddle again?' is the wordplay.
I cannot really understand how this works, but
'again?' could be 're' (prefix meaning 'again') and 're' is located in the answer.
The remaining letters 'strain' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for restrain that I've seen before include "Prevent (from excess)" , "Stop" , "Tie up - arrest" , "Keep in check" , "In arrest (anagram)" .)