Orders UK fills for expert (7)
I believe the answer is:
skilful
'expert' is the definition.
('skilful' can be a synonym of 'expert')
'orders uk fills' is the wordplay.
'orders' indicates anagramming the letters.
'uk'+'fills'='ukfills'
'ukfills' anagrammed gives 'SKILFUL'.
'for' acts as a link.
(Other definitions for skilful that I've seen before include "exhibiting crafts" , "Very adept and proficient" , "with expertise" , "Capable" , "Adept, expert" .)