愈发 is an adverb meaning 'increasingly' or 'more and more', used to describe a gradual intensification of a state, quality, or action over time. The character 愈 (yù) originally means 'to heal' but in this compound functions as a classical prefix indicating 'the more... the more...', while 发 (fā) here does not mean 'to send out' but serves as a grammatical intensifier — together, they form a fixed literary adverbial phrase emphasizing progressive change.

This word is commonly found in written Chinese and formal spoken contexts — such as news reports, essays, or speeches — rather than casual daily conversation. It typically modifies adjectives (e.g., 愈发紧张), verbs (e.g., 愈发重视), or entire clauses, and usually appears before the predicate. While similar to 越来越, 愈发 carries a slightly more refined, concise, and sometimes solemn tone, often implying observable, steady escalation rather than mere repetition.