* Τοξικός (toxikós): This is the most direct translation, derived from the word "toxin." It's suitable when referring to something poisonous or containing toxins, like a toxic substance.
* Επικίνδυνος (epikíndynos): This means "dangerous" or "hazardous." This is a good choice if you're talking about something toxic in the sense of being harmful or posing a risk.
* Μολυσματικός (molysmatiós): This translates to "contagious" or "infectious." Use this if the "toxicity" refers to something spreading disease or contamination.
* Επιβλαβής (epivlabís): This means "harmful" or "damaging." It's a good general-purpose word if the toxicity is causing damage or harm in a broad sense.
For a more nuanced translation, provide the context in which you're using the word "toxic." For example, "toxic relationship" would likely be best translated as τοξική σχέση (toxikí schésí), using the direct translation of "toxic."