It's my shiftiness that's somewhat obscure! (5)
I believe the answer is:
misty
'obscure' is the definition.
(I've seen this in another clue)
'it's my shiftiness that's somewhat' is the wordplay.
'it's my' anagrams to 'MISTY'.
Though, I am not sure how the anagram is indicated.
Can you help me to learn more?
(Other definitions for misty that I've seen before include "Hazy" , "Dim, indistinct" , "Dim, obscure, clouded" , "unclear" , "Foggy; dim in outline" .)