Monarch consumed food; seconds after it repeats (8)
I believe the answer is:
iterates
'repeats' is the definition.
(I know this)
'monarch consumed food seconds after it' is the wordplay.
'monarch' becomes 'er' (abbreviation for Elizabeth Regina, British Queen).
'consumed food' becomes 'ate' (I've seen this before).
'seconds' becomes 's'.
'after' means one lot of letters go next to another.
'er'+'ate'+'s'='erates'
'erates' after 'it' is 'ITERATES'.
(Other definitions for iterates that I've seen before include "Repeats in treaties" , "States repeatedly" , "Goes over again" , "Says again" , "Stated repeatedly in treatise" .)