Exaggerated role by Phi in developing foremost of crosswords (10)
I believe the answer is:
hyperbolic
'exaggerated' is the definition.
('hyperbolic' can be a synonym of 'exaggerated')
'role by phi in developing foremost of crosswords' is the wordplay.
I cannot really understand how this works, but
'by' could be 'per' and 'per' is found within the answer.
'of' could be 'o' and 'o' is located in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hyperbolic that I've seen before include "exaggerated" , "Like some curves" .)