Busy fellow with a companion, possibly bearing nuts (5)
I believe the answer is:
beech
'busy fellow with a companion possibly bearing nuts' is the definition.
I can't tell whether this defines the answer.
'busy fellow with a companion' is the wordplay.
'busy fellow' becomes 'bee' (I can't justify this - if you can you should believe this answer much more).
'with' means one lot of letters go next to another.
'a companion' becomes 'ch' (Companion of Honour).
'bee'+'ch'='BEECH'
Can you help me to learn more?
(Other definitions for beech that I've seen before include "Wood" , "Deciduous tree with smooth grey bark" , "Tree variety" , "Common deciduous tree" , "Type of tree" .)