他的结论基于一个从未明说的隐含假设。

His conclusion depends on a ___tacit assumption never made explicit.

我们之间有一种默契，不需要明说就能理解对方的意思。

There was a ___tacit agreement between us without any words spoken.

他们之间有一种默契，不需要言语就能理解对方。

There was a ___tacit understanding between them that didn't require words.