Resembling or containing slag, which is a stony waste matter separated from metals during the smelting or refining of ore. The slaggy residue left over from the smelting process was disposed of carefully.
Covered with or consisting of slag, often used to describe a surface or area. The old industrial site was slaggy, with remnants of the past smelting operations scattered around.
(slang, derogatory) Sexually promiscuous or slatternly. He called her outfit slaggy, saying it was inappropriate for the formal dinner.