The Collaborative International Dictionary
Poisonous \Poi"son*ous\, a.
Having the qualities or effects of poison; venomous; baneful;
--Shak. -- Poi"son*ous*ly, adv. -- Poi"son*ous*ness, n.
n. The state or quality of being poisonous.
Usage examples of "poisonousness".
But that molecular biological mechanism for the frogs' poisonousness could be considered an unimportant detail because many other poisonous chemicals would have worked equally well.