Alert as comedian struck (4,2)
I believe the answer is:
with it
'alert as comedian struck' is the definition.
I can't tell whether this defines the answer.
'comedian struck' is the wordplay.
'comedian' becomes 'wit' (a witty person).
'struck' becomes 'hit' (I've seen this in another clue).
'wit'+'hit'='WITH-IT'
Can you help me to learn more?
(Other definitions for with it that I've seen before include "Intelligently aware; trendy" , "Fashion conscious; alert and aware" , "Fashionable" , "cool" , "as well?" .)