One may be caught out, losing this (6)
I believe the answer is:
wicket
'out losing this' is the definition.
The definition suggests a singular noun which matches the answer.
'one may be caught' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'caught' could be 'c' (cricket abbreviation) and 'c' is found in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for wicket that I've seen before include "Small gate - dismissal at cricket" , "Small gate, for a cricketer?" , "that first-class delivery may take" , "Means of access" , "One of the 21 acrosses" .)