Proficiency displayed in task illustrated (5)
I believe the answer is:
skill
'proficiency' is the definition.
(I've seen this in another clue)
'displayed in task illustrated' is the wordplay.
'displayed in' indicates a hidden word.
'SKILL' is hidden within 'task illustrated'.
(Other definitions for skill that I've seen before include "Prowess" , "Special ability" , "Craft; dexterity" , "Expertise; art" , "Ability acquired by training" .)