noun
prostration
prah-STRAY-shun/prɑːˈstreɪʃn/
Extreme physical weakness or exhaustion.
After intense effort, the adult lies face down in prostration.

Etymology
Being thrown down or lying down in submission extended to the weakness of being physically laid low.
More examples
- The illness leaves her in complete prostration.
- Days of heat bring him close to prostration.
Forms
prostration
Similar words
- exhaustion
- Extreme tiredness without necessarily implying collapse.
- debility
- A state of physical weakness, often from illness.