Replace drink when meeting spy (8)
I believe the answer is:
supplant
'replace' is the definition.
(I know that replace can be written as supplant)
'drink when meeting spy' is the wordplay.
'drink' becomes 'sup' (to sup is to drink).
'when meeting' is a charade indicator (letters next to each other).
'spy' becomes 'plant' (someone planted somewhere to spy).
'sup'+'plant'='SUPPLANT'
(Other definitions for supplant that I've seen before include "Displace" , "Oust" , "take another's place" , "Supersede and replace" .)