The most difficult threads to disentangle (7)
I believe the answer is:
hardest
'the most difficult' is the definition.
(I've seen this in another clue)
'threads to disentangle' is the wordplay.
'threads' anagrams to 'HARDEST'.
However, I am not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for hardest that I've seen before include "most difficult to unravel" , "Red hats (anag.)" , "Most difficult or firm" , "Trashed (anag) - most oppressive" .)