Bound to be a bit excited when agitated (4)
I believe the answer is:
tied
'bound' is the definition.
('tie' can be a synonym of 'bind')
'a bit excited when agitated' is the wordplay.
I cannot really understand how this works, but
'when' could be 'e' (I've seen this in other clues) and 'e' is found within the answer.
The remaining letters 'tid' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for tied that I've seen before include "Drew; bound" , "Fastened, bound" , "Bound; placed equal" , "United" , "eg Scored 1-1" .)