Wrench in heap? (4)
I believe the answer is:
rick
I believe this is a double definition.
'wrench' is the first definition.
(I know that wrench can be written as rick)
'heap?' is the second definition.
(I know that rick is a type of stack)
'in' acts as a link.
(Other definitions for rick that I've seen before include "Stack, of hay say" , "Strain; stack" , "Sprain; hay pile" , "Wrench; haystack" , "Muscle affliction" .)