Pleasure: I’m holding an ace and four kings (7)
I believe the answer is:
william
'four kings' is the definition.
(William I, William II, William III and William IV)
'pleasure i'm holding an ace' is the wordplay.
'pleasure' becomes 'will' (at will means at one's pleasure).
'holding' means one lot of letters goes inside another.
'an ace' becomes 'a' (abbreviation).
'im' enclosing 'a' is 'iam'.
'will'+'iam'='WILLIAM'
'and' is the link.
(Other definitions for william that I've seen before include "I am a weakish speller (anag) -- author" , "-- Caxton, early printer" , "Prince Harry's brother" , "- - Wordsworth" , "Shakespeare or Pitt, say" .)