Spoil line and get knotted (7)
I believe the answer is:
tangled
'knotted' is the definition.
('tangle' can be a synonym of 'knot')
'spoil line and get' is the wordplay.
'spoil' indicates an anagram.
'line' becomes 'l' (used when specifying particular lines from a poem).
'l'+'and'+'get'='landget'
'landget' anagrammed gives 'TANGLED'.
(Other definitions for tangled that I've seen before include "Complex" , "''Oh what a ... web we weave / when first we practise to deceive'' (Walter Scott)" , "Twisted into confused mass" , "In a knotty mess" , "Caught" .)