Servant on the spot, turning up during supper? (6)
I believe the answer is:
menial
'servant' is the definition.
(menial is a kind of servant)
'on the spot turning up during supper?' is the wordplay.
'on the spot' becomes 'in' (I've seen this in other clues).
'turning up' shows that the letters should be reversed in order.
'during' indicates putting letters inside.
'supper?' becomes 'meal' (supper is a kind of meal).
'in' written backwards gives 'ni'.
'ni' inserted into 'meal' is 'MENIAL'.
(Other definitions for menial that I've seen before include "(Of work) unskilled" , "Servile of lowly" , "Demeaning" , "(Suitable for) servant of low status" , "(Of job) low in prestige" .)