Damage extremely lucrative career (6)
I believe the answer is:
hurtle
'career' is the definition.
(I've seen this before)
'damage extremely lucrative' is the wordplay.
'damage' becomes 'hurt' (hurt is a kind of damage).
'extremely' says to hollow out the word (remove centre letters).
'lucrative' with its middle removed is 'le'.
'hurt'+'le'='HURTLE'
(Other definitions for hurtle that I've seen before include "Proceed quickly and noisily" , "Move fast; rhymes with marine reptile" , "Lacking speed" , "Career (along)" , "Run headlong" .)