Complicated word or phrase (8)
I believe the answer is:
mouthful
'complicated word or phrase' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mouthful that I've seen before include "Outburst of strong language" , "Complicated word or phrase" , "Difficult word or phrase to pronounce" , "Something difficult to say or understand" .)