Rotund describes a person with a round, fat body. English speakers use it with a little smile — not as a doctor’s word, and not usually as a hard insult, more like a cartoon of someone round as a ball. You will meet it in stories and light description more than in everyday chat; a friend would more often say round or chubby. Because it sounds Latin and a bit formal, it can feel teasing rather than blunt. It still talks about body shape, so use it with care about real people in front of you. The everyday cousin of the same old root is simply round.

圓胖的（帶幽默、偏書面上的說法，不是醫護用語）。