English and American soldiers rejected evacuation (5)
I believe the answer is:
enema
'evacuation' is the definition.
(I've seen this before)
'english and american soldiers rejected' is the wordplay.
'english' becomes 'E' (abbreviation).
'and' is a charade indicator (letters next to each other).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'soldiers' becomes 'men' (men can mean a group of soldiers).
'rejected' shows that the letters should be reversed in order.
'a'+'men'='amen'
'amen' written backwards gives 'nema'.
'e'+'nema'='ENEMA'
(Other definitions for enema that I've seen before include "Medical liquid introduced anally" , "Suppository" , "Stern action from nurse perhaps" , "Bowel evacuator" , "Colonic irrigation" .)