Cheers killed off peripheral characters in time (7)
I believe the answer is:
slainte
'cheers' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'killed off peripheral characters in time' is the wordplay.
'killed off' becomes 'slain' (slaying is a kind of killing. I am not sure about the 'off' bit.).
'peripheral characters in' means to remove the middle letters (outside letters).
'time' with its middle removed is 'te'.
'slain'+'te'='SLAINTE'
Can you help me to learn more?
(Other definitions for slainte that I've seen before include "Toast" , "your health!" .)