Swarm starting to encircle every man (4)
I believe the answer is:
teem
'swarm' is the definition.
(I know that swarm can be written as teem)
'starting to encircle every man' is the wordplay.
'starting' indicates taking the first letters.
'man' becomes 'm' (M is an abbreviation for male or masculine).
The initial letters of 'to encircle every' is 'tee'.
'tee'+'m'='TEEM'
(Other definitions for teem that I've seen before include "Pullulate" , "Seethe" , "Bucket down" , "Rain hard" , "Move in large numbers" .)