Example sentences
shēn身tǐ体zhòng重yào要。
Health is important.
tā他shēn身tǐ体bù不shū舒fú服。
He's not feeling well.
About this word
身 is the body, the torso from the neck down, and 体 is a person's frame or substance. Chinese stacked two near-synonyms into a single two-syllable word, which is how a large share of modern Chinese vocabulary was built. 身体 leans physical and practical: 你身体好吗 asks after someone's health the way you might ask after their car. 身子 is the same thing in a more casual, flesh-and-bone register.
The story behind the character
身
身 is a person drawn from the side, with the belly given extra weight. Some scholars read the shape as a pregnant woman, the torso curved forward, one leg showing. Either way it began as a body and narrowed to mean exactly that. Xu Shen wrote 身，躳也, the body, a person's own frame.
体
体 is 亻 (person) with 本 (root) on the right. A person's root, their frame, their foundation. The traditional 體 is 骨 (bone) with 豊 giving the sound, and Xu Shen defined it as the sum of the body's twelve parts. The simplified 体 is not a modern invention; it is an old popular form that won.