Attacks small hill with 1,000 soldiers at the rear (6)
I believe the answer is:
storms
'attacks' is the definition.
(storming is a kind of attacking)
'small hill with 1000 soldiers at the rear' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'hill' becomes 'tor' (tor is a kind of hill).
'with' is a charade indicator (letters next to each other).
't000' becomes 'M' (roman numeral).
'at the rear' indicates one should take the final letters.
The last letter of 'soldiers' is 's'.
's'+'tor'+'m'+'s'='STORMS'
(Other definitions for storms that I've seen before include "Weather periods with force 10 winds" , "Weather periods when winds are force 11" , "Violent winds and rain" , "French Mediterranean coast" , "They occur when winds reach force 10" .)