Something hard that can give you an edge (5)
I believe the answer is:
steel
'hard that can give you an edge' is the definition.
'steel' can be an answer for 'hard'. I am unsure of the rest of the definition.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for steel that I've seen before include "Structural metal alloy" , "Knife-sharpener" , "May be cold" , "Make hard and unfeeling" , "Hard, strong, grey alloy" .)