IPA: /ˈtæsɪtli/
KK: /ˈtæsɪtli/
In a way that is understood or agreed upon without being openly expressed; implied or unspoken.
They tacitly agreed to the plan without discussing it.
Tacitly → It is formed from "tacitus" (meaning silent or unspoken) and the adverbial suffix "-ly" (meaning in a manner of). The word "tacitly" means in a silent or unspoken manner, implying agreement or understanding without explicit expression.
Think of something being 'silent' ('tacitus') and done 'in a manner' ('-ly') — that's why tacitly means doing something without speaking about it.