Consumer's holiday without son (5)
I believe the answer is:
eater
'consumer's' is the definition.
(consume can mean to eat)
'holiday without son' is the wordplay.
'holiday' becomes 'easter' (Easter is a Christian holiday).
'without' is a deletion indicator.
'son' becomes 's' (genealogical abbreviation for son).
'easter' with 's' removed is 'EATER'.
(Other definitions for eater that I've seen before include "Fruit (but not a cooker)" , "type of fruit" , "Apple, perhaps" , "One consuming" , "Type of apple" .)