Philosopher left old Anglicans hosting king (5)
I believe the answer is:
locke
'philosopher' is the definition.
(Locke is an example)
'left old anglicans hosting king' is the wordplay.
'left' becomes 'l' (common abbreviation**).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'anglicans' becomes 'ce' (Church of England).
'hosting' means one lot of letters goes inside another.
'king' becomes 'k'.
'ce' enclosing 'k' is 'cke'.
'l'+'o'+'cke'='LOCKE'
(Other definitions for locke that I've seen before include "John -, seventeenth to eighteenth century English philosopher" , "A philosopher; sounds like strand of hair" , "English empiricist philosopher, d. 1704" .)