Spike in Falmouth or Newquay (5)
I believe the answer is:
thorn
'spike' is the definition.
(I've seen this before)
'in falmouth or newquay' is the wordplay.
'in' indicates a hidden word.
'THORN' is hidden in the letters of 'falmouth or newquay'.
(Other definitions for thorn that I've seen before include "Letter written long ago" , "Pointed growth" , "Pointed extension of leaf" , "Spine on some plants" , "eg Prickle on rose" .)