Steadfast, strong (8)
I believe the answer is:
stalwart
I believe this clue is a double definition.
'steadfast' is the first definition.
(I've seen this in another clue)
'strong' is the second definition.
(thesaurus)
(Other definitions for stalwart that I've seen before include "Sturdy, tenacious and tough" , "husky" , "Valiant" , "Reliable; sturdy" , "Loyal, reliable and hardworking" .)