1 Shush!, Quiet!, Be or Keep quiet or silent or still!, Hold your tongue!, Mum's the word!, Slang Shut up!, Clam up!, Shut your trap!, Button your lip!, Shut your gob!, Brit Belt up!, US Hush up!, Shut your face!, US dialect Hush your mouth!:
Hush! You're in a library.
2 shush, silence, still, quiet:
I wish she'd hush the child's wailing.
3 suppress, mute, soften, soft-pedal, whisper:
They spoke in hushed tones.
4 Usually, hush up. suppress, repress, quash, cover up, hide, conceal, keep quiet, Colloq squelch:
They tried to hush up the news about his extramarital affairs.
5 soothe, allay, calm, quiet, mollify, pacify, placate, tranquillize:
Our worst fears were hushed by father's comforting words.
6 silence, quiet, stillness, peace, tranquillity:
A hush came over the crowd as she rose to speak.