Adverb
Usually written in kana
1. anywhere; for all time; to the ends of the earth
どこまでも広がる大きな空があるんだって。They say there is a vast sky that stretches on endlessly.
2. through thick and thin; come hell or high water; to the bitter end; to the utmost
どこまでも共に戦うわ。I'll fight by your side to the very end.
3. persistently; stubbornly
彼はどこまでも私の邪魔をしたいらしい。It seems he's determined to keep getting in my way.
4. in all respects; on every point
5. thoroughly; exhaustively
彼はどこまでも真面目な人だ。He is earnest through and through.