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firmly; flatly; resolutely; decisively; absolutely; definitely
definitely (wrong, different, etc.); absolutely
by far; far and away; by a long shot; hands down
この件について私は断然反対の立場です。
On this matter I am absolutely opposed.
断然こちらの方が良いと私は思います。
I definitely think this one is better.
断然やるべきだと会議で主張しました。
I insisted that it should definitely be done.