Challenge for the ambitious governor disheartened by casual staff (6,4)
I believe the answer is:
greasy pole
'challenge for the ambitious' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'governor disheartened by casual staff' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters) (the middle or heart is removed).
'by casual' becomes 'easy' (similar in meaning. I am not sure about the 'by' bit.).
'staff' becomes 'pole' (I've seen this before).
'governor' with its middle removed is 'gr'.
'gr'+'easy'+'pole'='GREASY POLE'
Can you help me to learn more?
(Another definition for greasy pole that I've seen is " hard way to the top".)