‘发胖’ is a verb meaning ‘to gain weight’—typically in a neutral, observational, or medical context. It does not carry strong positive or negative connotations like ‘变胖’ (which can sound more judgmental) or ‘长胖’ (more colloquial and general). The first character 发 (fā) here functions as a verb prefix indicating the onset or development of a state, while 胖 (pàng) means ‘fat’ or ‘chubby’. Together, they describe the process of becoming heavier, often due to lifestyle, aging, hormonal changes, or health conditions.

This term is commonly used in health discussions, doctor-patient conversations, nutrition advice, or self-reflective statements about body changes. It’s slightly more formal than everyday slang but less clinical than terms like ‘体重增加’ (tǐzhòng zēngjiā, ‘weight gain’). It’s rarely used for animals or inanimate objects—its primary domain is human physiology and wellness.