tight-lipped 三缄其口的;口紧的;缄口不语的;守口如瓶的;双唇紧闭的(尤指因生气)

【例句】
Oh you're putting me in a difficult situation now. I wanted to tell you but I also promised I would stay tight- lipped .
唉呦，你让我好为难。我很想告诉你，可是我也答应会守口如瓶的。

On the third measure, however, most firms remained tight-lipped.
尽管如此，对第三项调查，多数公司三缄其口。