devil's dust
Any type of powder or dustlike substance whose use or effect is considered to be…Any type of powder or dustlike substance whose use or effect is considered to be harmful or malevolent.
Meaning
2 senses(informal, slang, uncountable)Any type of powder or dustlike substance whose use or effect is considered to be harmful or malevolent.
(obsolete, uncountable)Shoddy produced by a devil (machine for tearing or cutting rags, cotton, etc).
Lessons for this word
1 lessons- A1Countable and uncountable nouns — Because it can be uncountable