Simple manoeuvres for forces (6)
I believe the answer is:
impels
'forces' is the definition.
('impel' can be a synonym of 'force')
'simple manoeuvres' is the wordplay.
'manoeuvres' is an anagram indicator.
'simple' is an anagram of 'IMPELS'.
'for' is the link.
(Other definitions for impels that I've seen before include "Spurs" , "Urges forward" , "Drives or forces" , "Drives on in simple way" , "Urges or drives to do something" .)