Affirmation of artistry (3)
I believe the answer is:
tis
'affirmation' is the definition.
Although both the answer and definition are nouns, they are not in the same form of the noun.
'of artistry' is the wordplay.
'of' indicates the answer is hidden within the clue.
'TIS' is hidden in the letters of 'artistry'.
Can you help me to learn more?
(Other definitions for tis that I've seen before include "It is shortened" , "That thing's" , "Contraction of it is" , "... the season to be jolly" , "Sequel to "Angela's Ashes"" .)