If I were blank I would be this! (8)
I believe the answer is:
clueless
'if i were blank i would' is the definition.
I can't judge whether this defines the answer.
'this' is the wordplay.
I cannot really see how this works, but
'this' could be 'clue' (the clue referring to itself!) and 'clue' is found in the answer.
The remaining letters 'less' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'be' acts as a link.
Can you help me to learn more?
(Other definitions for clueless that I've seen before include "Ignorant (informal)" , "Stupid (so unable to do crossword?)" , "Without any understanding" , "such a crossword can't be solved!" , "With no idea" .)