Kill many among rodents going back in time (8)
I believe the answer is:
decimate
'kill' is the definition.
(decimating is a kind of killing)
'rodents going back in time' is the wordplay.
'rodents' becomes 'mice' (mouse is a kind of rodent).
'going back' is a reversal indicator.
'in' means one lot of letters goes inside another.
'time' becomes 'date' (date is a kind of time**).
'mice' backwards is 'ecim'.
'ecim' going within 'date' is 'DECIMATE'.
'many among' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for decimate that I've seen before include "Medicate (anag.)" , "Kill one in ten (as Romans did as punishment for mutiny)" , "slaughter" , "severely cut" , "By killing" .)