The state or quality of being unsuited or inappropriate.(noun)
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Use "unsuitableness" in a sentence
"What would be best advised, then, if it be found so hurtful and so unequal to suppress opinions for the newness or the unsuitableness to a customary acceptance, will not be my task to say."
"I mean to say that the argument in prospect is likely to be too much for you, out of your depth and beyond your strength, and I should be afraid that the stream of my questions might create in you who are not in the habit of answering, giddiness and confusion of mind, and hence a feeling of unpleasantness and unsuitableness might arise."
"The judge shall consider and determine the suitableness or unsuitableness of age in marriage; he shall make an inspection of the males naked, and of the women naked down to the navel."