Expected a nobleman to lose a kilo (3)
I believe the answer is:
due
'expected' is the definition.
(I've seen this before)
'a nobleman to lose a kilo' is the wordplay.
'a nobleman' becomes 'duke' (duke is a kind of nobleman).
'to lose' indicates named letters should be taken away.
'a kilo' becomes 'k' (phonetic alphabet: alpha, bravo, charlie etc.).
'duke' with 'k' taken out is 'DUE'.
(Other definitions for due that I've seen before include "Expected; proper" , "Appropriate - fee - requiring payment" , "Entitlement" , "Requisite" , "Required; proper" .)