### Clue: Old boy has clean turned around after direction to stop drinking (5,2)
### Answer: SOBER UP 
 ### Explanation: Definition: to stop drinking
 [ OB(abbrev. for "old boy" of a school, say) **contained in**(has … around) **reversal of**(… turned) PURE(clean;unadulterated) ] **placed after**(after) S(abbrev. for "south", the direction).