Mechanical screw failing (4)
I believe the answer is:
vice
This clue could be a double definition.
'mechanical screw' is the first definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'failing' is the second definition.
(a moral failing)
Can you help me to learn more?
(Other definitions for vice that I've seen before include "Gripper - depravity" , "Evil < number two" , "Bad habit - it grips" , "Is the gripping tool evil?" , "Deputy with bad habit?" .)