tacitly

/ˈtæsɪtli/

Things that are done tacitly assume there is an unspoken understanding between the people or groups involved. Walking into your friend's house without knocking first tacitly expresses that you are like family, not a guest.

Leaving the seat at the head of the table for the guest of honor is a way to tacitly express respect and observe a custom. Maybe you never talked to your friends about sitting together at lunch — you just started doing it one day — you tacitly plan to continue eating together. The Latin root of tacitly is tacitus, which means "something that is silent or performed without words."

Definitions of tacitly

1. adverb

   in a tacit manner; by unexpressed agreement
   “they are tacitly expected to work 10 hours a day”