Repeat, angry, about the missing middle (7)
I believe the answer is:
iterate
'repeat' is the definition.
(synonyms)
'angry about the missing middle' is the wordplay.
'angry' becomes 'irate' (irate can mean angry or annoyed).
'about' indicates putting letters inside.
'the missing middle' becomes 'te' (I can't justify this - if you can you should give a lot more credence to this answer).
'irate' going around 'te' is 'ITERATE'.
Can you help me to learn more?
(Other definitions for iterate that I've seen before include "Say again, repeat" , "Recapitulate" , "Repeat, state again" , "Utter or perform repeatedly" , "State repeatedly, say again" .)