그러니까
geureonikka · TOPIK 1
so, therefore
그러니까 = 그러(하) like that + 니까 because → because it is like that, so
Built from 그러하다 (to be like that) plus the reason ending -니까 (because). Literally: because it is so. That is why it works as so or therefore, and as a filler meaning I mean or exactly when you agree with someone.