Disconcert rodent with title it lost (6)
I believe the answer is:
rattle
'disconcert' is the definition.
(I know that disconcert can be written as rattle)
'rodent with title it lost' is the wordplay.
'rodent' becomes 'rat' (rat is a kind of rodent).
'with' is a charade indicator (letters next to each other).
'lost' indicates named letters should be taken away.
'title' with 'it' removed is 'tle'.
'rat'+'tle'='RATTLE'
(Other definitions for rattle that I've seen before include "Noisy baby's toy" , "Disconcert - English conductor, b. 1955" , "Vibrate noisily" , "Noisy type of snake" , "Infant's toy" .)