How good the yarn was you found perturbing? (8)
I believe the answer is:
rattling
'perturbing?' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'how good the yarn was you' is the wordplay.
I cannot quite see how this works, but
'good' could be 'g' (abbreviation) and 'g' is found in the answer.
The remaining letters 'rattlin' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'found' is the link.
Can you help me to learn more?
(Other definitions for rattling that I've seen before include "indication of loose parts?" , "worrying" , "Quick and energetic" , "Is loosely attached item" , "Noisily shaking (as in good yarn)" .)