Annoying elements to scheme (10)
I believe the answer is:
nettlesome
'annoying' is the definition.
('nettlesome' can be a synonym of 'annoying')
'elements to scheme' is the wordplay.
'scheme' is an anagram indicator.
'elements'+'to'='elementsto'
'elementsto' anagrammed gives 'NETTLESOME'.
(Other definitions for nettlesome that I've seen before include "causing irritation" , "annoying" .)