Free from dirt, stain, or impurities; unsoiled. Free from foreign matter or pollution; unadulterated: clean air; clean drinking water. Not infected: a clean wound. Producing relatively little pollution: a clean fuel; a cleaner, more efficient engine. Producing relatively little radioactive fallout or contamination: a clean nuclear bomb. Having no imperfections or blemishes; regular or even: a clean edge; a smooth, clean joint. Not ornate or intricate; spare: "the clean lines and exquisite proportions of early modernism\u201d ( Judith Thurman). Sharply defined; clear-cut: a clean outline against the sky. Free from clumsiness; deft; adroit: a clean throw. Devoid of restrictions or encumbrances: a clean bill of health. Thorough; complete: a clean getaway. Having few alterations or corrections; legible: clean manuscript. Blank: a clean page. Morally pure; virtuous: led a clean life. Having no marks of discredit or offense: a clean voting record. Fit for all readers, listeners, or audiences; not ribald or obscene: a clean joke. Honest or fair: a clean fighter; a clean competition. Slang Not carrying concealed weapons or drugs. Slang Innocent of a suspected crime. Informal Free from narcotics addiction. Informal Showing no evidence of using banned or performance-enhancing substances: proven to be clean before the race. So as to be unsoiled: wash the dishes clean. In a fair manner: played the game clean. In a clean or nonpolluting manner: a fuel that burns clean. Informal Entirely; wholly: clean forgot the appointment.