Boss important to menial worker (6)
I believe the answer is:
donkey
'menial worker' is the definition.
'boss important' is the wordplay.
'boss' becomes 'don' (I can't justify this - if you can you should believe this answer much more).
'important' becomes 'key' (similar in meaning).
'don'+'key'='DONKEY'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for donkey that I've seen before include "Domestic animal" , "Burro" , "dope" , "Foolish person; animal" , "Beasts of burden" .)