Hard (5)
'hard' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for difficult that I've seen before include "Requiring much effort" , "Challenging" , "Trying" , "Demanding" , "Hard, not easy" .)
'hard' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for solid that I've seen before include "Firm - sound - reliable" , "Hard and compact" , "Rock-hard" , "Neither liquid nor gas" , "Dense" .)
'hard' is the definition.
(associated in meaning)
This is all the clue.
(Other definitions for tough that I've seen before include "Strong or leathery" , "Strict, uncompromising" , "Hard to cut or chew" , "Strong - ruffian" , "Difficult to cut and chew" .)
(Other definitions for die that I've seen before include "a block?" , "one's cast" , "Perish" , "one proverbially straight" , "A device used for casting metal" .)
'hard' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for steely that I've seen before include "Hard and metallic" , "Coldly determined" , "As hard, or grey, as metal" , "With (cold) resolve" , "Determined; severe" .)