The others rushed outside: I hold back (8)
I believe the answer is:
restrain
'hold back' is the definition.
('restrain' can be a synonym of 'hold back')
'the others rushed outside i' is the wordplay.
'the others' becomes 'rest' (I've seen this in other clues).
'rushed' becomes 'ran'.
'outside' means one lot of letters goes inside another.
'ran' placed around 'i' is 'rain'.
'rest'+'rain'='RESTRAIN'
(Other definitions for restrain that I've seen before include "Stop" , "bar" , "Tie up - arrest" , "stay" , "Limit" .)