A Christian American lancing boils (8)
I believe the answer is:
anglican
'a christian' is the definition.
(Anglican is an example)
'american lancing boils' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'boils' indicates anagramming the letters (I've seen 'boiled' mean this (letters cooked or boiled into a new form)).
'lancing' is an anagram of 'nglican'.
'a'+'nglican'='ANGLICAN'
(Other definitions for anglican that I've seen before include "As believer" , "Relating to the Church of England" , "Within the Church of England's communion" , "C of E person" , "Christian in communion with the see of Canterbury" .)