Confidence about oddly absurd artwork that's outstanding (3-6)
I believe the answer is:
bas-relief
'artwork that's outstanding' is the definition.
I can't judge whether this defines the answer.
'confidence about oddly absurd' is the wordplay.
'confidence' becomes 'belief' (I've seen this before).
'about' indicates putting letters inside.
'oddly' indicates alternate letters (letters in odd-numbered positions).
The alternating letters of 'absurd' are 'asr'.
'belief' going around 'asr' is 'BAS-RELIEF'.
Can you help me to learn more?
(Other definitions for bas-relief that I've seen before include "Sculpture with carvings projecting slightly from background" , "As febrile as sculpture with figures slightly projecting from background" , "Sculpture with slightly raised figures" .)