Shaw play? I'm not sure (3,5,3,4)
I believe the answer is:
you never can tell
'shaw play?' is the definition.
'you never can tell' can be an answer for 'play?' (I've seen this before). I'm unsure of the 'shaw' bit.
'i'm not sure' is the wordplay.
I cannot really understand how this works, but
'not' could be 'nt' (synonyms) and 'nt' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for you never can tell that I've seen before include "Doubt expressed," , "Exclamation on the unpredictability of life" , "It's always impossible to predict" , "Play" , "song written by Chuck Berry" .)