optimist

Describes someone who is always optimistic, regardless of the circumstances.

Similar to 'eternal optimist', often used humorously to describe someone whose optimism cannot be changed.

Describes someone who is foolishly or unrealistically optimistic.

相変わらずの楽天家

A fixed phrase used to describe someone's characteristically optimistic reaction or statement.

その人らしい楽観的な反応や発言を表現する定型句です。