Initially means at the very beginning. Initially refused, initially thought, initially it worked.
It nearly always sets up a change: initially he refused implies that he later did not, which is why the word is so useful for narrative. It is more formal than at first and means the same. Note initial as adjective and noun; and that initially properly refers to the start of a described sequence rather than to the start of time in general.
1adverbinitiallyAt the very beginning.
“Initially, I didn't like the city, but now I love it.”
initially is a reference to the start.
Latin
initiālis
Middle French
initial
English
initial
English, today
initially
Built from
From initial + -ly. initial Borrowed from Middle French initial, from Latin initiālis. From Middle French initial or directly from its Latin - etymon initiālis (“of the beginning, incipient, initial”), from initium (“a going in, entrance”), from ineō (“to go into, enter”), from in (“in”) + ire (“to go”).
Etymology from Wiktionary, CC BY-SA