重(zhòng) - heavy; serious, severe; strong, pronounced in Mandarin

重 (zhòng) is heavy in the physical sense, and by extension serious or pronounced: 病很重 is a bad illness, 口音很重 is a thick accent, 责任很重 is a weighty responsibility. It is the opposite of 轻 (qīng, light).

The character is the classic Mandarin trap because it has two readings. As zhòng it means heavy; as chóng it means again or repeated, and that is the reading in 重新 (chóng xīn, afresh) and 重复 (chóng fù, to repeat). Same character, different word, and only context tells you which. Read 重要 as zhòng yào and 重来 as chóng lái.

To ask about weight, Mandarin uses 多重 rather than a noun: 这个箱子多重？ How heavy is this box? For a person's weight the usual question is 你多重 or, more politely, 你的体重是多少.