Briefly study issue with some common sense (6)
I believe the answer is:
reason
'some common sense' is the definition.
(thesaurus)
'briefly study issue' is the wordplay.
'briefly' means to remove the last letter.
'study' becomes 'read' ('read' can be a synonym of 'study').
'issue' becomes 'son' (issue can mean someone's offspring).
'read' with its final letter taken off is 'rea'.
'rea'+'son'='REASON'
'with' is the link.
(Other definitions for reason that I've seen before include "Purpose" , "brain operations" , "Justification or motive" , "Sanity, the ability to think" , "Justification needed" .)