Uncompromising (4-7)
'uncompromising' is the definition.
(adamant can mean stubborn or determined)
This is the entire clue.
(Other definitions for adamant that I've seen before include "Fully determined" , "Insistent, inflexible" , "Refusing to budge" , "Positive or intransigent" , "Hard stone" .)
(Other definitions for hard-hitting that I've seen before include "Uncompromisingly direct and honest" , "Strongly worded" .)
'uncompromising' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for stern that I've seen before include "Strict; severe" , "Looking severe" , "Unyielding part of the ship" , "Grim; severe" , "Strict, austere" .)
'uncompromising' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for tough that I've seen before include "Resilient; thug" , "Strong - difficult" , "Challenging" , "Rugged" , "Made to withstand abuse" .)