Clever opener from Halifax Town (5)
I believe the answer is:
neath
'town' is the definition.
(town in Wales)
'clever opener from halifax' is the wordplay.
'clever' becomes 'neat' (I've seen this before).
'opener from' suggests taking the first letters (I've seen 'openers from' mean this (letters which open the words are used)).
The first letter of 'halifax' is 'h'.
'neat'+'h'='NEATH'
(Other definitions for neath that I've seen before include "Welsh industrial town" , "not on top" , "Welsh team" , "Welsh rugby club" , "Town near Swansea" .)