Haystack (4)
I believe the answer is:
rick
'haystack' is the definition.
(I know that haystack can be written as rick)
This is the entire clue.
(Other definitions for rick that I've seen before include "Strain; stack" , "Stack of hay - pain in the neck" , "result of making hay?" , "Stack, of hay say" , "Haystack; sprain" .)