The fellow had got angry but concealed it (7)
I believe the answer is:
covered
'concealed it' is the definition.
I can't tell whether this definition defines the answer.
'the fellow had got angry' is the wordplay.
'the fellow' becomes 'cove' (British slang term).
'had' is a charade indicator (letters next to each other).
'got angry' becomes 'red' (I can't explain this - if you can you should give a lot more credence to this answer).
'cove'+'red'='COVERED'
'but' is the link.
Can you help me to learn more?
(Other definitions for covered that I've seen before include "Concealed; roofed over" , "Concealed; dealt with" , "Overlaid with something" , "given protection" , "Reported" .)