Go to smart meeting, secretly (8)
I believe the answer is:
trysting
'meeting secretly' is the definition.
(to tryst is to meet in secret)
'go to smart' is the wordplay.
'go' becomes 'try' (both can mean an attempt).
'to smart' becomes 'sting' (both can mean to burn or hurt).
'try'+'sting'='TRYSTING'
(Other definitions for trysting that I've seen before include "Agreeing to meet" , "meeting" .)