Set fire to hill by church (5)
I believe the answer is:
torch
'set fire to' is the definition.
(I've seen this before)
'hill by church' is the wordplay.
'hill' becomes 'tor' (tor is a kind of hill).
'by' says to put letters next to each other.
'church' becomes 'ch' (common abbreviation).
'tor'+'ch'='TORCH'
(Other definitions for torch that I've seen before include "Link" , "Set fire to - hand-held light" , "source of enlightenment" , "Small hand-held battery lamp" , "Such a love song" .)