| Idiom | Meaning | Example | 
| screw loose | 
(See a screw loose)
 | 
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| screw up | 
perform poorly, ruin it, blow it
 | 
I hope I don't screw up when I take my driver's test.
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| screw-up | 
a careless mistake, a bungled job
 | 
Those screw-ups were his fault. He forgot to order materials.
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| screw you [B] | 
the worst to you, up yours [B]
 | 
After I defeated him, he said, "Screw you." He hates to lose.
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| scrut | 
oh no, darn, nuts, rats
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Scrut! My bike has a flat tire!
 | 
| scum/scumbag | 
unpleasant person, dirty rat, slimebucket
 | 
"Scum!" he shouted at the man who had attacked his daughter.
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| search me | 
I do not have the answer, I do not know
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"Who took my Coke?" "Search me. I don't know."
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| second fiddle | 
(See play second fiddle)
 | 
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| second guess | 
guess what people think or what they will do
 | 
Don't try to second guess people. Ask them what you need to know.
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| second nature | 
natural ability or interest, talent
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Skating is second nature to Paul. He's got natural skating ability.
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