Easy shot, we hear, over key stronghold (7)
I believe the answer is:
citadel
'stronghold' is the definition.
(I know that citadel is a type of stronghold)
'easy shot we hear over key' is the wordplay.
'easy shot' becomes 'sitter' (term in various sports).
'we hear' indicates a 'sounds like' (homophone) clue.
'over' is a charade indicator (letters next to each other).
'key' becomes 'del' (del key on a keyboard).
'sitter' is a homophone of 'cita'.
'cita'+'del'='CITADEL'
(Other definitions for citadel that I've seen before include "place of refuge" , "Kremlin" , "secure place" , "Stronghold (of the Salvation Army?)" , "Bastion" .)