身体 is the formal reading; 体 (body) is used in everyday speech.
Common collocations
- 身体検査 (physical examination; also a security body search)
- 身体障害 (physical disability)
- 身体能力 (physical ability)
Similar words
- 体: everyday word for body; more casual
- 肉体: physical body, often contrasted with mind/spirit