Difficult or intricate (6)
I believe the answer is:
tricky
I believe this clue is a double definition.
'difficult' is the first definition.
(similar in meaning)
'intricate' is the second definition.
(thesaurus)
(Other definitions for tricky that I've seen before include "Complicated" , "Crafty or difficult" , "Awkward - dishonest" , "Crafty, foxy, slippery" , "Difficult; sly" .)