Live wire round pole? One's had it! (5)
I believe the answer is:
goner
'it' is the definition.
The definition suggests a singular noun which matches the answer.
'live wire round pole? one's' is the wordplay.
'live wire round' becomes 'go' (I can't justify this - if you can you should believe this answer much more).
'pole?' becomes 'n' (abbreviation for North, as in North Pole).
'one' becomes 'er' (I've seen this in other clues).
'go'+'n'+'er'='GONER'
'had' acts as a link.
Can you help me to learn more?
(Other definitions for goner that I've seen before include "One doomed to die" , "person about to depart" , "Dead duck" , "No-hoper" , "Article ruined" .)