First in competition, winning trophy (3)
I believe the answer is:
cup
'trophy' is the definition.
(cup is a kind of trophy)
'first in competition winning' is the wordplay.
'first in' indicates taking the first letters.
'winning' becomes 'up' (I've seen this in other clues).
The first letter of 'competition' is 'c'.
'c'+'up'='CUP'
(Other definitions for cup that I've seen before include "Drinking bowl" , "Trophy, drink" , "Award; mug" , "Chalice; trophy" , "Sort of cake" .)