Robber's daughter taking vermouth, propping up bar (6)
I believe the answer is:
bandit
'robber's' is the definition.
(bandit is a type of robber)
'daughter taking vermouth propping up bar' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'taking' says to put letters next to each other.
'vermouth' becomes 'it' (short for 'Italian vermouth' as in 'gin and it').
'propping up' is a charade indicator (letters next to each other) (in a down clue, some letters hold others up).
'bar' becomes 'ban' (bar can mean to ban or prohibit).
'd' put next to 'it' is 'dit'.
'dit' put after 'ban' is 'BANDIT'.
(Other definitions for bandit that I've seen before include "Member of a gang of robbers" , "Crook" , "Highwayman" , "Dan bit the robber badly" , "Outlaw, brigand" .)