Castigate for having left Uncle out? (4)
I believe the answer is:
slam
'castigate for' is the definition.
'slam' can be an answer for 'castigate' (I've seen this in another clue). I'm not certain of the 'for' bit.
'left uncle out?' is the wordplay.
'left' becomes 'l' (common abbreviation).
'uncle' becomes 'sam' (Uncle Sam is an example).
'out?' is an insertion indicator.
'l' put into 'sam' is 'SLAM'.
'having' is the link.
Can you help me to learn more?
(Other definitions for slam that I've seen before include "Shut violently" , "major contract" , "Winning all (or all but one) of the tricks in bridge" , "A grand one is 13 tricks" , "Hit hard" .)