Defecate is a formal term, more clinical than everyday words like 'poop'. The doctor asked if she was able to defecate normally.
Pro Tip 2/3
Public Sensitivity
Using 'defecate' in public or social situations might be viewed as indelicate or impolite. In polite company, he referred to needing to defecate indirectly.
Pro Tip 3/3
Medical Context
Defecate is used frequently in medical or health contexts to discuss bowel movements. Patients are often asked about their ability to defecate when discussing digestive health.