|Origin:||Latin substantia, from substare 'to stand under'|
a particular type of solid, liquid, or gas:
The leaves were covered with a strange sticky substance.
dangerous/toxic/hazardous/poisonous etc substance
harmful substances in the atmosphere
Plutonium 238 is one of the most toxic substances known to man.
illegal/banned/prohibited/controlled substance (=used especially about illegal drugs)
Police found an illegal substance in his car.
if something has substance, it is true:
truth[uncountable usually in questions and negatives] formal
There is no substance to the rumours (=they are untrue).
without substance (=untrue)
O'Connell's remarks are completely without substance.
the most important ideas contained in an argument or piece of writing [= essence]:
The substance of his argument was that people on welfare should work.
What she said, in substance, was that the mayor should resign.
importance [= significance]:
It was an entertaining speech, but it lacked substance (=there was no important information in it).
matters/issues of substance
We should be discussing matters of substance.
5 British English literary
a rich man or woman