Light eater primarily tucking into cured meat (6)
I believe the answer is:
beacon
'light' is the definition.
(I've seen this before)
'eater primarily tucking into cured meat' is the wordplay.
'primarily' says to take the initial letters.
'tucking into' means one lot of letters goes inside another.
'cured meat' becomes 'bacon' (I've seen this before).
The initial letter of 'eater' is 'e'.
'e' placed into 'bacon' is 'BEACON'.
(Other definitions for beacon that I've seen before include "A warning light as on headland" , "Shiner" , "Radio transmitter for positioning" , "Fire on a hill, lit as a signal" , "Warning or guiding device" .)