Wordy fellow engrossed in poetry (7)
I believe the answer is:
verbose
'wordy' is the definition.
(I know that wordy can be written as verbose)
'engrossed in poetry' is the wordplay.
'engrossed' becomes 'bo' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'poetry' becomes 'verse' (synonyms).
'bo' going into 'verse' is 'VERBOSE'.
'fellow' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for verbose that I've seen before include "Talkative, given to saying too much" , "Observe (anag) -- long-winded" , "not given to Trappist ways" , "Circumlocutory" , "Garrulous" .)