Nail top of sheet on front pile (5)
I believe the answer is:
stack
'front pile' is the definition.
'stack' can be an answer for 'pile' (synonyms). I'm unsure of the 'front' bit.
'nail top of sheet on' is the wordplay.
'nail' becomes 'tack' (tack is a kind of nail).
'top of' suggests taking the first letters.
'on' says to put letters next to each other.
The initial letter of 'sheet' is 's'.
'tack' after 's' is 'STACK'.
Can you help me to learn more?
(Other definitions for stack that I've seen before include "Aggregation or heap" , "Pile of hay" , "functioned successfully in Scotland" , "Place in ordered pile" , "Tall chimney" .)