Answer negative from Macron immediately (4)
I believe the answer is:
anon
'immediately' is the definition.
(anon can mean soon or promptly)
'answer negative' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'negative' becomes 'non' (similar in meaning).
'a'+'non'='ANON'
'from macron' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for anon that I've seen before include "Presently - or unknown" , "Presently - unattributed" , "Soon - nobody knows me" , "In the near future" , "Of unknown authorship" .)