Throw candleholder into mire (10)
I believe the answer is:
disconcert
'throw' is the definition.
(synonyms)
'candleholder into mire' is the wordplay.
'candleholder' becomes 'sconce' (candle holder attached to a wall).
'into' means one lot of letters goes inside another.
'mire' becomes 'dirt'.
'sconce' going into 'dirt' is 'DISCONCERT'.
(Other definitions for disconcert that I've seen before include "Disturb, unsettle" , "Throw" , "upset" , "Dismay" , "Shake up" .)