This is the 11296th most frequent Russian word.
деловое
Businesslike; related to business or work.
The word "деловито" here describes the manner of behavior of the person, emphasizing efficiency and professionalism.
Он ведет себя очень деловито.
He conducts himself very businesslike.
In this sentence, "деловое" qualifies "мероприятие" to indicate that the event is related to professional or business activities.
Мы посетили деловое мероприятие вчера.
We attended a business event yesterday.
The word "деловой" describes "журнал," specifying that its content pertains to business domains.