An adverb indicating a fairly high degree; considerably, quite, or rather (usually written in kana).
このレストランはかなり高いけど味は本格的だ。
This restaurant is quite expensive, but the food is authentic.
彼はかなり疲れているように見えた。
He looked fairly tired.
今回のテストはかなり難しかった。
This test was pretty difficult.