Lives about the flanks (7)
I believe the answer is:
resides
'lives' is the definition.
(to reside somewhere is to live there)
'about the flanks' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'the flanks' becomes 'sides'.
're'+'sides'='RESIDES'
(Other definitions for resides that I've seen before include "stayed in Scotland" , "stays in Peebles" , "Lives, dwells" , "stays required" , "Sojourns" .)