結構
Kekkou
けっこう
One of the most confusing words for Japanese learners because it changes meaning with context: (1) 'quite/fairly' (kekkou oishii = quite tasty), (2) 'enough/no thank you' (mou kekkou desu = I'm fine, no more), (3) 'surprisingly' (kekkou muzukashii = surprisingly difficult). Note that 'kekkou oishii' can subtly imply 'better than expected,' so for a straightforward compliment, 'meccha oishii' (super tasty) or 'kanari oishii' (really tasty) sounds more enthusiastic.
Examples
このラーメン、結構おいしいね
This ramen is kekkou good, actually.
Eating ramen with a friend
お茶のおかわりいかがですか？ ——いえ、結構です
More tea? — No, I'm fine, thank you. (Kekkou desu)
Declining a refill at a restaurant
日本語の文法って結構難しいよね
Japanese grammar is kekkou difficult, right?
結構歩いたね、もう1時間くらい歩いてる
We've walked kekkou far — it's been like an hour.