Meaning of “hush sth up” - Learner’s Dictionary

hush sth up

phrasal verb with hush uk us /hʌʃ/ verb [ T ]

to keep something secret, especially from the public, because it could cause embarrassment or trouble:

The whole affair was hushed up by the management.

(Definition of “hush sth up” from the Cambridge Learner’s Dictionary © Cambridge University Press)