Vain character from top firm about to be employed (7)
I believe the answer is:
'vain character' is the definition.
(peacock can figuratively mean a vain person)
'top firm about to be employed' is the wordplay.
I cannot quite understand how this works, but
'firm' could be 'co' (a firm is a company) and 'co' is present in the answer.
'about' could be 'c' (abbreviation for 'circa') and 'c' is located in the answer.
'top' could be 'peak' (synonyms) and 'peak' is present in the leftover letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
'from' acts as a link.
Can you help me to learn more?
(Other definitions for peacock that I've seen before include "Thomas Love --, author", "Male bird", "Showy fowl", "Bird noted for showy plumage", "Type of butterfly".)