Was ruffled, one understood (8)
I believe the answer is:
gathered
'understood' is the definition.
('gather' can be a synonym of 'understand')
'was ruffled one' is the wordplay.
I cannot quite see how this works, but
'one' could be 'the' (both can introduce a definite example of something) and 'the' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for gathered that I've seen before include "Concluded from evidence" , "Gleaned" , "The grade (anag.)" , "Understood" , "Got together - tucked in" .)