Grim hotel by a road (4)
I believe the answer is:
'grim' is the definition.
'hotel by a road' is the wordplay.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'by' means one lot of letters go next to another.
'road' becomes 'rd' (abbreviation).
(Other definitions for hard that I've seen before include "Solid; difficult" , "impenetrable" , "Intensely" , "Newspaper's sure" , "Emergency lane" .)