1. superlative form of clean; most free from dirt, marks, or stains
2. superlative form of clean; most morally pure or innocent
3. superlative form of clean; most free from pollution or contamination

Examples

• This is the cleanest room in the entire house.
• She always keeps her car the cleanest of all her friends.
• The mountain spring water is the cleanest source available.
• He has the cleanest record of any candidate running for office.
• This beach is considered the cleanest in the region.
• The cleanest energy sources are wind and solar power.