Put soldiers in retreat for August? (5)
I believe the answer is:
royal
'for august?' is the definition.
(I've seen this before)
'put soldiers in retreat' is the wordplay.
'put' becomes 'lay' (as in laying or putting something down).
'soldiers' becomes 'or' (military abbreviation for other ranks).
'in retreat' says the letters should be written backwards.
'lay'+'or'='layor'
'layor' in reverse letter order is 'ROYAL'.
(Other definitions for royal that I've seen before include "Relating to kings/queens" , "Like Priam" , "With kingly status" , "William, say" , "Member of monarchy" .)