Humour, vacuous amusement in setting (7)
I believe the answer is:
placate
'humour' is the definition.
(to humour someone is to placate or appease them)
'vacuous amusement in setting' is the wordplay.
'vacuous' means to remove the middle letters.
'in' is an insertion indicator.
'setting' becomes 'place' (I've seen this in another clue).
'amusement' with its centre removed is 'at'.
'at' going within 'place' is 'PLACATE'.
(Other definitions for placate that I've seen before include "Mollify, soothe anger" , "'Pacify, appease (7)'" , "Mollify, appease" , "Make less angry" , "Make calm, conciliate" .)