Staunch supporter (4)
I believe this is a double definition.
'staunch' is the first definition.
(I've seen this before)
'supporter' is the second definition.
(I've seen this before)
(Other definitions for stem that I've seen before include "Slender upright part of wine glass" , "Staunch - stalk" , "Check - part of a plant" , "Halt flow" , "branch of family" .)
I believe this clue is a double definition.
'staunch' is the first definition.
(I've seen this before)
'supporter' is the second definition.
(stalwart is a kind of supporter)
(Other definitions for stalwart that I've seen before include "Sturdy, tenacious and tough" , "Steadfast" , "Loyal, reliable and hardworking" , "Tart laws could be strong and sturdy" , "Valiant" .)