Cleverly simple opener from Halifax Town (5)
I believe the answer is:
neath
'town' is the definition.
(town in Wales)
'cleverly simple opener from halifax' is the wordplay.
'cleverly simple' becomes 'neat' (I can't justify this - if you can you should believe this answer much more).
'opener from' says to take the initial letters (I've seen 'openers from' mean this (letters which open the words are used)).
The initial letter of 'halifax' is 'h'.
'neat'+'h'='NEATH'
Can you help me to learn more?
(Other definitions for neath that I've seen before include "Town near Swansea" , "Welsh team" , "Under, poetically" , "Lower than - a town in West Glamorgan" , "River" .)