a chemical or other agent that damages cellular DNA, resulting in mutations or cancer

A chemical capable of causing damage to DNA. Such damage can potentially lead to the formation of a malignant tumor, but DNA damage does not lead inevitably to the creation of cancerous cells. [See: Evidence Supporting the Mutagenicity of Fluoride | Fluoride & Cancer

toxic to the genome (i.e., DNA)

causing damage to DNA, which may but does not necessarily result in a mutation and cancer.

Toxic to the genetic material (i.e., genes, made up of DNA) in an organism's cells.

Capable of altering the structure of DNA and causing mutations.

Causing harm to an organism by damaging the organism's DNA.

Damaging to DNA; pertaining to agents known to damage DNA.

Genotoxic substances are those chemical compounds capable of causing genetic mutation and of contributing to the development of tumors. Radiation is also considered to be genotoxic.