Rest is disturbed before tea's served (6)
I believe the answer is:
siesta
'rest' is the definition.
(thesaurus)
'is disturbed before tea's served' is the wordplay.
'disturbed' indicates an anagram.
'before' is a charade indicator (letters next to each other).
'served' indicates an anagram.
'is' is an anagram of 'si'.
'teas' with letters rearranged gives 'esta'.
'si'+'esta'='SIESTA'
(Other definitions for siesta that I've seen before include "A mid-day nap in Spain" , "PM snoozing?" , "Spanish afternoon nap" , "Afternoon relaxation" , "Afternoon nap in Cadiz" .)