American guy expected to host duke (4)
I believe the answer is:
dude
'american guy' is the definition.
'expected to host duke' is the wordplay.
'expected' becomes 'due' (similar in meaning).
'to host' indicates putting letters inside.
'duke' becomes 'd'.
'due' placed around 'd' is 'DUDE'.
(Other definitions for dude that I've seen before include "Dandy - US or Canadian city dweller" , "Stylish and confidant man" , "Man (US colloq.)" , "Stylish man (US)" , "Stylish and affected man" .)