1. (n.) The extraneous matter or impurities which rise to the surface of liquids in boiling or fermentation, or which form on the surface by other means; also, the scoria of metals in a molten state; dross.

2. (v.) refuse; recrement; anything vile or worthless.

3. (v. t.) To take the scum from; to clear off the impure matter from the surface of; to skim.

4. (v. t.) To sweep or range over the surface of.

5. (v. i.) To form a scum; to become covered with scum. Also used figuratively.

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