Resentful state of English male had effect over period on hospital department (12)

'resentful state' is the definition.
'embitterment' can be an answer for 'state' (embitterment is a kind of state). I'm not sure about the 'resentful' bit.

'english male had effect over period on hospital department' is the wordplay.
I cannot quite understand how this works, but
'english' could be 'e' (abbreviation) and 'e' is found within the answer.
'male' could be 'm' (common abbreviation) and 'm' is found within the answer.
'period' could be 'term' (term is a kind of period) and 'term' is found in the answer.
'hospital department' could be 'ent' and 'ent' is found in the answer.
The remaining letters 'bit' 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).

'of' acts as a link.

Can you help me to learn more?