Troops from south coming in roaring drunk (8)
I believe the answer is:
garrison
'troops' is the definition.
(garrison is a kind of troops)
'south coming in roaring drunk' is the wordplay.
'south' becomes 'S' (abbreviation).
'coming in' means one lot of letters goes inside another.
'drunk' indicates an anagram.
'roaring' anagrammed gives 'garrion'.
's' put inside 'garrion' is 'GARRISON'.
'from' acts as a link.
(Other definitions for garrison that I've seen before include "Troops defending a town or fortress" , "(Soldiers guarding) fortified place" , "Military base" , "Military stronghold" , "troops in base" .)