I eat after ten (6)
I believe the answer is:
iodine
'i' is the definition.
(I is the chemical symbol for iodine)
'eat after ten' is the wordplay.
'eat' becomes 'dine' (dining is a kind of eating).
'after' is a charade indicator (letters next to each other).
'ten' becomes 'io'.
'dine' put after 'io' is 'IODINE'.
(Other definitions for iodine that I've seen before include "Solution applied to wounds as an antiseptic" , "Element used in medicine, photography and dyes" , "Black/violet element" , "Halogen element, atomic no 53" , "Disinfectant made from seaweed" .)