It means a pure substance comprised of atoms or molecules. It is not a perjorative. Use “synthetic chemical”, “harmful chemical”, “dangerous chemical”, “carcinogenic chemical” (although the “-ic chemical” is redundant). Not just “chemical”. Water is a chemical*. Air is a mixture of chemicals. “Chemical” is not shorthand for “nasty industrial solvent”. Learn that.

*Dihydrogen monoxide is a good example of how easy it is to  scare people by using “chemicalish” names. Use the term “amino acid” in a non-scientific context and you’d probably have to explain they’re not like sulphuric acid. I won’t continue this rant onto standards of scientific education, but I could. So easily.

 [Note: this was sparked by a Food Tech mark scheme which allowed "don't use chemicals" (meaning artificial additives) as an answer. All food contains chemicals. All food is organic (contains carbon).]