Show lack of interest in English rugby (5)
I believe the answer is:
shrug
'show lack of interest' is the definition.
'in english rugby' is the wordplay.
'in' says the answer is hidden in the clue.
'SHRUG' is hidden within 'english rugby'.
(Other definitions for shrug that I've seen before include "Gesture of resignation" , "Gesture of indifference or ignorance" , "Expressive movement of shoulders" , "Shoulder movement to indicate indifference" , "Body language indicating indifference or resignation" .)