'weight-losing' originates from the combination of 'weight' and 'losing', where 'weight' refers to the heaviness of a person or thing, and 'losing' is the present participle of 'lose', meaning to become lighter or less.

'weight-losing' evolved from the phrase 'losing weight', which has been used in English since the 19th century to describe the process of reducing body mass.

Initially, it meant 'to become lighter', but over time it evolved into its current meaning of 'referring to the process of reducing body mass'.