一声不吭

一聲不吭
yīshēngbùkēng
to not say a word

CEDICT

Entry Composition

1 一声 yīshēng first tone in Mandarin (high, level tone)
2 不 bù
  1. no; not so
  2. (bound form) not; un-
3 吭 kēng to utter