Shore (up) (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
prop
'shore up' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for prop that I've seen before include "player involved in scrum" , "See 5" , "A rigid supprot or piece of satge furniture (4)" , "One is usually among the strongest and heaviest rugby players" , "Back up" .)