Note dreadful lion close by, taking a twisting route (3-6)
I believe the answer is:
non-linear
'taking a twisting route' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'note dreadful lion close' is the wordplay.
'note' becomes 'n' (abbreviation).
'dreadful' indicates an anagram.
'close' becomes 'near' (synonyms).
'lion' with letters rearranged gives 'onli'.
'n'+'onli'+'near'='NON-LINEAR'
'by' acts as a link.
Can you help me to learn more?
(Another definition for non-linear that I've seen is " Not in a straight line".)