Spark can still flicker, outside of the faint-hearted (9)
I believe the answer is:
scintilla
'spark' is the definition.
(I've seen this before)
'still flicker outside of the faint-hearted' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'faint' could be 'ill' (similar in meaning) and 'ill' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'can' acts as a link.
Can you help me to learn more?
(Other definitions for scintilla that I've seen before include "Minute spark" , "Slight amount" , "The smallest amount" , "littlest bit" , "Tiny, scarcely detectable amount" .)