Disk tending to be a failure (6)
I believe the answer is:
floppy
'disk' is the definition.
(I know that floppy is a type of disk)
'tending to be a failure' is the wordplay.
I cannot really understand how this works, but
'failure' could be 'flop' (flop is a kind of failure) and 'flop' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for floppy that I've seen before include "Hanging loosely" , "Flexible computer disc" , "Old-fashioned disk" , "Tending to hang loosely" , "Sort of disk" .)