The charge is that the word “Easter” derives from the name of a pagan fertility goddess “Eostre.” It is said that Christians took over a spring festival devoted to this deity. But this article by British historian Anthony McRoy debunks that claim: Was Easter Borrowed from a Pagan Holiday? | Christian History.
Briefly, the connection to Eostre was made by the Venerable Bede, the medieval church historian, but we can find no other mention of the goddess or any festival associated with her. Prof. McRoy accounts for what may have been Bede’s misunderstanding with some other etymological accounts of the origin of our word “Easter.”
Besides, English and the other Germanic languages are the only languages that calls the Festival of the Resurrection “Easter.” Everyone else calls it some version of “Pascha,” which derives from the Hebrew word for “Passover.” And the holiday was celebrated extremely early in the church’s history, evidently by the 2nd century. And its original celebration in the Middle East and around the Mediterranean sea shows no connection at all to any pagan festivals.