Tea is prepared after Sunday afternoon nap (6)
I believe the answer is:
siesta
'afternoon nap' is the definition.
(I've seen this before)
'tea is prepared after sunday' is the wordplay.
'prepared' indicates anagramming the letters.
'after' says to put letters next to each other.
'sunday' becomes 's'.
'tea'+'is'='teais'
'teais' with letters rearranged gives 'iesta'.
'iesta' after 's' is 'SIESTA'.
(Other definitions for siesta that I've seen before include "Afternoon break" , "Spanish afternoon nap" , "Daytime nap" , "PM snoozing?" , "A Spanish mid-day nap" .)