Twelve ducks seen in outskirts of Newlyn (4)
I believe the answer is:
noon
'twelve' is the definition.
(I've seen this before)
'ducks seen in outskirts of newlyn' is the wordplay.
'ducks' becomes 'oo' (I've seen this in other clues).
'seen in' means one lot of letters goes inside another.
'outskirts of' means to remove the middle letters.
'newlyn' with its centre taken out is 'nn'.
'oo' placed inside 'nn' is 'NOON'.
(Other definitions for noon that I've seen before include "Twelve during daylight" , "Twelve o'clock in the day" , "when only mad dogs go out?" , "12 pm" , "See 8" .)