underweight

US /ˌʌn.dɚˈweɪt/
UK /ˌʌn.dɚˈweɪt/
"underweight" picture
1.

sottopeso, magro

below a weight considered normal or healthy

:
The doctor said the baby was slightly underweight.
Il medico ha detto che il bambino era leggermente sottopeso.
She was concerned about her dog being underweight.
Era preoccupata che il suo cane fosse sottopeso.