You, for an hour, stand outside (4)
I believe the answer is:
thee
'you' is the definition.
(I've seen this in other clues)
'an hour stand outside' is the wordplay.
'an hour' becomes 'h'.
'stand' becomes 'tee' (I've seen this before).
'outside' is an insertion indicator.
'h' going inside 'tee' is 'THEE'.
'for' is the link.
(Other definitions for thee that I've seen before include "'U'" , "Quaker 'you'" , "You in the olden days" , "Poetically you" , "you many years ago" .)