adjective

1. 1. free from dirt, contamination, impurities, etc.; unsoiled; unstained
   2. free from disease, infection, radioactivity, etc.
2. ☆ producing little immediate fallout: said of nuclear weapons
3. producing few or no pollutants; non-polluting clean energy
4. recently laundered; fresh and unused
5. 1. morally pure; sinless
   2. not obscene or indecent a clean joke
6. fair; sportsmanlike a rough but clean contest
7. keeping oneself or one's surroundings clean; neat and tidy
8. 1. shapely; well-formed a clean profile
   2. trim; not ornate clean architectural lines
9. skillful; deft a clean stroke
10. having no obstructions, flaws, or roughnesses; clear; regular a clean drain
11. entire; complete; thorough a clean sweep
12. having few corrections; legible clean copy for the printer
13. with nothing in it or on it clean pockets, a clean sheet of paper
14. ☆ Slang
    1. not carrying a weapon, illegal drugs, etc.
    2. innocent of an alleged crime
    3. free from the use or presence of or from addiction to narcotics or other illicit drugs
15. Bible
    1. free from ceremonial defilement
    2. fit for food: said of certain animals

Etymology: ME clene < OE clæne, clean, pure < IE *ĝ(e)lēi- < base *ĝel-, to gleam > OIr gel, gleaming, white, OHG kleini, gleaming, bright, fine (> Ger klein, small)

adverb

1. in a clean manner
2. Informal completely; wholly clean forgotten

Etymology: OE clæne

transitive verb

1. to make clean
2. to remove (dirt, impurities, etc.) in making clean
3. to empty or clear
4. to prepare (fish, fowl, etc.) for cooking
5. ☆ Slang to take away or use up the money or possessions of: often with out
6. Weight Lifting to lift (a barbell) from the floor to the shoulders in one continuous movement

intransitive verb

1. to be made clean
2. to perform the act of cleaning