The adjective pure describes something that's made of only one substance and is not mixed with anything else. For example, your favorite soft, warm winter scarf might be made from pure merino wool.
Anything that's uncontaminated by extra, unnecessary, or unclean substances is pure. You can swim in pure water or wear a necklace that's made of pure silver. Pure can also mean "complete" or "absolute," especially when it describes happiness. A religious meaning of pure is "free from sin", good or wholesome. The Latin word purus, "clean or unmixed," is the root of pure.