Foremost of directors study fear (5)
I believe the answer is:
dread
'fear' is the definition.
('dread' can be a synonym of 'fear')
'foremost of directors study' is the wordplay.
'foremost of' indicates taking the first letters.
'study' becomes 'read' ('read' can be a synonym of 'study').
The initial letter of 'directors' is 'd'.
'd'+'read'='DREAD'
(Other definitions for dread that I've seen before include "Trepidation" , "Anticipate with fear" , "Be scared of" , "Terror" , "Be very averse to" .)