Boringly long-winded (7)
I believe the answer is:
verbose
'boringly long-winded' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for verbose that I've seen before include "Circumlocutory" , "With an excess of words" , "Wordy, prolix" , "Using more words than are needed" , "Garrulous" .)