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 tell whether this works.
'note dreadful lion close' is the wordplay.
'note' becomes 'n' (abbreviation).
'dreadful' is an anagram indicator.
'close' becomes 'near' (similar in meaning).
'lion' anagrammed gives 'onli'.
'n'+'onli'+'near'='NON-LINEAR'
'by' is the link.
Can you help me to learn more?
(Another definition for non-linear that I've seen is " Not in a straight line".)