When others know, everyone starts to be alert to injustice (4)
I believe the answer is:
woke
'be alert to injustice' is the definition.
I can't judge whether this definition defines the answer.
'when others know everyone starts' is the wordplay.
'starts' indicates taking the first letters.
The initial letters of 'when others know everyone' is 'WOKE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for woke that I've seen before include "Ceased to sleep" , "Came to" , "Roused from sleep" , "Stopped sleeping" .)