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 tell whether this defines the answer.
'confidence about oddly absurd' is the wordplay.
'confidence' becomes 'belief' (I've seen this before).
'about' means one lot of letters goes inside another.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
The alternate letters of 'absurd' are 'asr'.
'belief' placed 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" .)