Cure (6)
'cure' is the definition.
(synonyms)
This is all the clue.
(Other definitions for remedy that I've seen before include "A cure, for disease or other ill" , "Countermeasure" , "Cure or redress" , "Treatment; redress" , "Medicine, treatment" .)
(Other definitions for heyday that I've seen before include "Period of one's greatest success" , "Period of greatest success and popularity" , "The time of greatest success or prosperity" , "Highest period in someone's career" , "golden age" .)
'cure' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for heal that I've seen before include "Cure, mend" , "Cure, make well" , "Make whole and healthy" , "Become healthy again" , "Make better" .)
'cure' is the definition.
(antidote is a kind of cure)
This is all the clue.
(Other definitions for antidote that I've seen before include "Medicine to counteract poison" , "A remedy for poison (8)." , "Counteracting medicine" , "Counter-agent" , "Donate it to anti-poison agent" .)