Person who holds up gown worn by bishop before Queen (6)
I believe the answer is:
robber
'person who holds up' is the definition.
'robber' can be an answer for 'person' (robber is a kind of person). I'm not certain of the remainder of the definition.
'gown worn by bishop before queen' is the wordplay.
'gown' becomes 'robe' (synonyms).
'worn by' is an insertion indicator (outside letters are worn by those on the inside).
'bishop' becomes 'B' (chess abbreviation).
'before' means one lot of letters go next to another.
'queen' becomes 'r' (abbreviation for regina, e.g. in ER ).
'robe' enclosing 'b' is 'robbe'.
'robbe'+'r'='ROBBER'
Can you help me to learn more?
(Other definitions for robber that I've seen before include "One who thieves" , "Mugger" , "Violent thief" , "Highwayman, for example" , "Property stealer" .)