Discerning, unusual taste when out of uniform (6)
I believe the answer is:
astute
'discerning unusual taste' is the definition.
'astute' can be an answer for 'discerning' (I've seen this in another clue). I'm not sure about the 'unusual taste' bit.
'when out of uniform' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'out of uniform' becomes 'tute' (I can't justify this - if you can you should give a lot more credence to this answer).
'as'+'tute'='ASTUTE'
Can you help me to learn more?
(Other definitions for astute that I've seen before include "Having hardheaded intelligence" , "Sharp and clever" , "Shrewd, canny" , "Nymph who was transformed into a laurel tree to escape Apollo" , "Percipient" .)