1. poisonous or harmful to living organisms
Usage: archaic or nonstandard form of ‘toxic’

Examples

• The old manuscript described the plant as toxical to livestock.
• Modern usage prefers ‘toxic’ over the archaic ‘toxical’.
• The researcher noted the toxical effects of the compound.
• Few contemporary dictionaries list ‘toxical’ as standard.
• The toxical nature of the substance was well documented in historical texts.