Look for last of killers? I’m scared! (4)
I believe the answer is:
seek
'look for' is the definition.
(synonyms)
'last of killers? i'm scared' is the wordplay.
'last of' suggests the final letters.
'i'm scared' becomes 'eek' (exclamation showing fear).
The final letter of 'killers' is 's'.
's'+'eek'='SEEK'
(Other definitions for seek that I've seen before include "Ask for (permission)" , "Try to locate or reach" , "Try to find" , "Attempt - search" , "Attempt to find; ask for" .)