Wet area spoils start of holiday (5)
I believe the answer is:
marsh
'wet area' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'spoils start of holiday' is the wordplay.
'spoils' becomes 'mars' ('mar' can be a synonym of 'spoil').
'start of' says to take the initial letters.
The first letter of 'holiday' is 'h'.
'mars'+'h'='MARSH'
Can you help me to learn more?
(Other definitions for marsh that I've seen before include "Swampy ground" , "Quagmire" , "eg Romney" , "Bog, swamp" , "Wetland" .)