益发 is an adverb meaning 'increasingly' or 'more and more', used to emphasize a gradual intensification of a state, quality, or action. The character 益 (yì) originally means 'to increase' or 'benefit', while 发 (fā) here functions as a complement indicating emergence or intensification — together they form a fixed compound expressing progressive change. It’s formal but common in both written and spoken Mandarin, especially in descriptive or literary contexts.

This word typically modifies adjectives (e.g., 益发明显), verbs (e.g., 益发喜爱), or entire clauses. It usually appears before the predicate and carries a neutral-to-positive connotation, though context determines emotional tone. Unlike colloquial alternatives like 越来越, 益发 sounds slightly elevated and is often found in essays, news reports, or thoughtful speech — not in casual texting or slang.