Teresa is out for the holiday (6)
I believe the answer is:
easter
'the holiday' is the definition.
(Easter is a Christian holiday)
'teresa is out' is the wordplay.
'is out' is an anagram indicator (out can mean wrong or inaccurate).
'teresa' with letters rearranged gives 'EASTER'.
'for' acts as a link.
(Other definitions for easter that I've seen before include "Church festival" , "Christian festival of celebration" , "Time to celebrate" , "Sort of tide" , "See art at this time of year" .)