The Collaborative International Dictionary
Poisonousness
Poisonous \Poi"son*ous\, a.
Having the qualities or effects of poison; venomous; baneful;
corrupting; noxious.
--Shak. -- Poi"son*ous*ly, adv. --
Poi"son*ous*ness, n.
Wiktionary
poisonousness
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.