Fine good-for-nothing over blade (7)
I believe the answer is:
fretsaw
'blade' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'fine good-for-nothing over' is the wordplay.
'fine' becomes 'f' (abbreviation in pencil classifications).
'good-for-nothing' becomes 'waster'.
'over' shows that the letters should be reversed in order.
'waster' backwards is 'retsaw'.
'f'+'retsaw'='FRETSAW'
Can you help me to learn more?
(Other definitions for fretsaw that I've seen before include "Woodcutter" , "Fine-toothed tool" , "Woodworking tool" , "Tool for cutting designs in wood" , "cutter" .)