n (phytopathology) A rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs.
n The bacterium, virus or fungus that causes such a condition.
n (by extension) Anything that impedes growth or development or spoils any other aspect of life.
v (transitive) To affect with blight; to blast; to prevent the growth and fertility of.
v (intransitive) To suffer blight.
v (transitive) To spoil, ruin, or destroy (something).