Modest dissent over committee's conclusion (6)
I believe the answer is:
demure
'modest' is the definition.
(I've seen this in another clue)
'dissent over committee's conclusion' is the wordplay.
'dissent' becomes 'demur' (I've seen this before).
'over' is a charade indicator (letters next to each other) (in a down clue, some letters go over others).
'conclusion' says to take the final letters.
The last letter of 'committee' is 'e'.
'demur'+'e'='DEMURE'
(Other definitions for demure that I've seen before include "Pretending to be quiet and serious" , "Modestly behaved" , "Prim, coy" , "(Of woman) modest, shy" , "Affectedly quiet and serious" .)