Fear primarily? Correct! (6)
I believe the answer is:
fright
'fear' is the definition.
('fright' can be a synonym of 'fear')
'primarily? correct' is the wordplay.
'primarily?' becomes 'f' (I can't explain this - if you can you should believe this answer much more).
'correct' becomes 'right' ('right' can be a synonym of 'correct').
'f'+'right'='FRIGHT'
Can you help me to learn more?
(Other definitions for fright that I've seen before include "A scare or shock" , "Panic" , "Sudden feeling of fear" , "Shock, sudden alarm" , "Terror" .)