A bully occasionally dismissed in a deft manner (4)
I believe the answer is:
ably
'in a deft manner' is the definition.
(I've seen this in another clue)
'a bully occasionally' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
The alternating letters of 'bully' are 'bly'.
'a'+'bly'='ABLY'
'dismissed' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ably that I've seen before include "With great skill" , "Masterfully" , "In proficient manner" , "well" , "In a competent fashion" .)