1. 未经治疗的
If an injury or illness is left untreated, it is not given medical treatment.

2. （有害物质）未经处理的
Untreated materials, water, or chemicals are harmful and have not been made safe.

3. （天然或原始物质）未经处理的，未加工过的
Untreated materials are in their natural or original state, often before being prepared for use in a particular process.

1. (of a specimen for study under a microscope) not treated with a reagent or dye

2. not subjected to chemical or physical treatment

e.g. an untreated fabric

3. not given medical care or treatment

e.g. an untreated disease
the untreated wounded lay on makeshift cots