‘纷至沓来’ is a literary four-character idiom meaning 'arriving in rapid, continuous, and overwhelming succession.' Each character contributes to this image: 纷 (fēn) suggests ‘numerous and scattered,’ like fluttering snow or falling petals; 至 (zhì) means ‘to arrive’; 沓 (tà) conveys ‘layer upon layer’ or ‘in abundance’; and 来 (lái) reinforces the sense of arrival. Together, they evoke a vivid picture of people, events, or things flooding in all at once—often with a tone of intensity or even slight overwhelm.

This idiom is commonly used in formal writing, news reports, and descriptive narratives—not in casual speech. It often modifies verbs like ‘涌来’ (surge in), ‘出现’ (appear), or ‘发生’ (occur), and typically describes abstract or collective phenomena: invitations, problems, opportunities, visitors, or challenges. While it can imply positivity (e.g., opportunities), context determines whether the tone is neutral, enthusiastic, or slightly negative (e.g., troubles piling up).