Here's a sign of stress! (6)
I believe the answer is:
accent
'a sign of stress' is the definition.
(I've seen this in another clue)
'here's' is the wordplay.
I cannot quite see how this works, but
'here' could be 'ent' (I've seen this in other clues) and 'ent' is present in the answer.
The remaining letters 'acc' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for accent that I've seen before include "Stress - manner of speech" , "Emphasis on syllable or local pronunciation" , "Distinctive local way of speaking" , "Pronunciation in a locality" , "Stress, emphasis" .)