Desire shown in Barrow is hot (4)
I believe the answer is:
wish
'desire' is the definition.
(I know this)
'in barrow is hot' is the wordplay.
'in' indicates a hidden word.
'WISH' can be found hidden inside 'barrow is hot'.
'shown' acts as a link.
(Other definitions for wish that I've seen before include "prayer" , "bid" , "Want (to do something)" , "Desire, hope" , "Request - yen" .)