Meaning of hush up

[Veki]

Test No. incompl/inter-42 "Keeping it Quiet", question 3

There were lots of rumours about what the son had done but as it was a very wealthy family the father tried very hard to ......... everything up.

(a) quiet
(b) hush
(c) stop
(d) silence

Test No. incompl/inter-42 "Keeping it Quiet", answer 3

There were lots of rumours about what the son had done but as it was a very wealthy family the father tried very hard to hush everything up.

Correct answer: (b) hush

Your answer was: correct
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Please help,
What does mean "HUSH everything UP?

Thank you a lot!

[Torsten]

If you hush something up you try to cover up a misdemeanor (a small or petty crime).
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