‘热心’ is an adjective meaning 'enthusiastic' or 'warm-hearted' — describing someone who shows genuine care, eagerness, and willingness to help others. Literally, 热 (rè) means 'hot' or 'intense', and 心 (xīn) means 'heart'; together they evoke the image of a 'hot heart' — full of warmth, energy, and emotional engagement. It emphasizes sincerity and proactive kindness, not just fleeting interest.

This word is commonly used to describe people’s attitudes in social, community, or volunteer contexts — for example, praising a neighbor who organizes clean-up events or a classmate who patiently tutors others. It carries positive moral connotations and often appears in formal praise, news reports about role models, or everyday compliments. While it can modify nouns (e.g., 热心的人), it more frequently follows verbs like 是, 很, or 非常 to form predicates (e.g., 他很热心). It’s not used for objects or abstract concepts alone — always tied to human intention and behavior.