schtum
adjective [ after verb ] informal (also shtum) uk/ʃtʊm/ us/ʃtʊm/
keep schtum (also stay schtum)（对某事）保持沉默
to not say anything about something
The actress is keeping schtum about who she's dating.
Would you hand the money in to the police or would you keep shtum?
Staying schtum about a problem doesn't mean the problem doesn't exist. 对一个问题保持沉默并不意味着这个问题就不存在了。