けっこう

けっこう is an adverb meaning "quite," "fairly," "rather," or "pretty (much)." It is used to indicate that something is more than expected or to a considerable degree, often carrying a nuance of mild surprise.

As an adverb: "quite / fairly / rather"

けっこう is placed before adjectives, verbs, or adverbs to express that the degree of something is higher than anticipated.

The nuance often implies "more than I thought" – the speaker is somewhat surprised by the degree. For example, saying けっこうおいしい suggests the food is tastier than expected.

As a response: "No, thank you" / "I'm fine"

けっこう can also be used on its own (often as けっこうです in polite speech) to politely decline an offer or to indicate that something is sufficient.

Be aware of this double meaning – depending on context, けっこうです can mean either "that's fine / satisfactory" or "no, thank you." The surrounding context and tone make the intended meaning clear.