na-adjective, noun
extreme busyness; hectic; multitude of tasks
Describes a state of being extremely busy with many things to do, often used in formal or written contexts. As a na-adjective, it modifies nouns (e.g., 繁多な日々). As a noun, it refers to the condition itself.
年末は業務が繁多で、休む暇もない。
At the end of the year, work is extremely busy, and there's no time to rest.
繁多なスケジュールをこなすのは大変だ。
It's tough to handle a hectic schedule.