Smart to corner right niche (6)
I believe the answer is:
cranny
'niche' is the definition.
(I've seen this in another clue)
'smart to corner right' is the wordplay.
I cannot quite understand how this works, but
'right' could be 'r' (common abbreviation) and 'r' is present in the answer.
'smart' could be 'canny' (similar in meaning) and 'canny' is found in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for cranny that I've seen before include "Secret place (searched after nook)" , "Small opening or crevice" , "Fissure - chink" , "Small narrow space" , "Crevice as hiding place" .)