The word malignant (evil, malicious) has the verb form "to malign" and the noun form "malignancy."
Malignant substance
The synonym of non malignant is benign.
If it is not known whether a tumor is benign or malignant, it is sometimes referred to as as "mass".
The tests show that the tumor is malignant.
Malignant would be the main answer, but another possible one is Cancerous.
The MRI of the patient is characteristic of malignant tumor. The malignant growth of the industries has spoiled the landscape.
Malign
Cancerous.
The tumor is malignant, which means cancerous, so I'll have to have it removed.
My grandmother had a tumor removed for a biopsy. Fortunately, it was not malignant! (Meaning it was not cancerous)
It is the deadliest form of skin cancer known.
Supercilium is another word for eyebrow. The plural form is supercillia.