A man of class, I reckon (3)
I believe the answer is:
sir
'a man' is the definition.
(sir is a kind of man)
'of class i reckon' is the wordplay.
'of' indicates the answer is hidden within the clue.
'SIR' is hidden within 'class i reckon'.
(Other definitions for sir that I've seen before include "address to teacher" , "Knight's title" , "Term of address for a gentleman" , "Formal and deferential address to a man" , "Polite form of address to a man" .)