Twisting intro so complicated (7)
I believe the answer is:
torsion
'twisting' is the definition.
(I've seen this in another clue)
'intro so complicated' is the wordplay.
'complicated' indicates anagramming the letters (a complex or confusing ordering of the letters).
'intro'+'so'='introso'
'introso' anagrammed gives 'TORSION'.
(Other definitions for torsion that I've seen before include "twist" , "Twisted position - no riots (anag)" , "Tortuous and twisted shape or position" , "White-berried parasite" , "Process of twisting" .)