adj

• Free of dirt, filth, or impurities (extraneous matter); not dirty, filthy, or soiled.
  "clean steel"
• Free of imperfections, blemishes, or defects.
  "Our team won, but it wasn't clean."
• Free of imperfections, blemishes, or defects.
• Free of immorality or criminality.
  "I'm clean, officer. You can go ahead and search me if you want."

noun

• (weightlifting) The first part of the event clean and jerk in which the weight is brought from the ground to the shoulders.
• (in the plural, metal music) Clear vocals, contrasted with death growls and screams.
  "When people complained the songs were too hard, Kyle's clean vocals could bail out the band. Adding cleans would set off a chain reaction though - Kyle's crisp, clear presence could be seen as "betraying" the raw assault that Mike inflicts on the fans with his screams and growls."

verb

• (transitive) To remove dirt from a place or object.
  "Can you clean the windows today?"
• (transitive) To tidy up, make a place neat.
  "Clean your room right now!"
• (transitive, climbing) To remove equipment from a climbing route after it was previously lead climbed.
• (intransitive) To make things clean in general.
  "She just likes to clean. That’s why I married her."