1. not given medical care or treatment
2. not processed or refined; in natural state
3. not subjected to a chemical or physical process

Examples

• The untreated infection spread rapidly.
• Untreated diabetes can lead to serious complications.
• The furniture was made from untreated wood.
• Untreated sewage polluted the river.
• She preferred untreated, organic cotton clothing.
• The untreated water contained harmful bacteria.
• His untreated anxiety affected his daily life.