The quality or state of being advisive; the characteristic of serving to give advice or counsel.
From advisive (advise plus -ive) plus the noun-forming suffix -ness. Since 'advisive' itself is rare, this derivative is even rarer in modern English.
This word is so obscure that it probably exists only in theoretical linguistic analysis—nobody speaks or writes 'advisiveness' in the real world, making it a perfect example of how language could create a word but chooses not to.
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