Hotel in capital starts to employ earnest old Jew (8)
I believe the answer is:
pharisee
'old jew' is the definition.
'hotel in capital starts to employ earnest' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' indicates putting letters inside.
'capital' becomes 'paris' (Paris is the capital of France).
'starts to' indicates taking the first letters.
The initial letters of 'employ earnest' is 'ee'.
'h' placed into 'paris' is 'pharis'.
'pharis'+'ee'='PHARISEE'
(Other definitions for pharisee that I've seen before include "Strict follower of Jewish law" , "Ancient Jewish sectarian" , "Hare pies for the Biblical pedant" , "Air sheep (anag.)" , "(Gospel) hypocrite" .)