I shall not lose you so soon, and Edward will have greater opportunity of improving that natural taste for your favourite pursuit which must be so indispensably necessary to your future felicity.
With the size and furniture of the house Mrs. Dashwood was upon the whole well satisfied; for though her former style of life rendered many additions to the latter indispensable, yet to add and improve was a delight to her; and she had at this time ready money enough to supply all that was wanted of greater elegance to the apartments.
Every qualification is raised at times, by the circumstances of the moment, to more than its real value; and she was sometimes worried down by officious condolence to rate good-breeding as more indispensable to comfort than good-nature.
On HER measures depended those of her two friends; Mrs. Jennings could not quit Cleveland during the Dashwoods’ stay; and Colonel Brandon was soon brought, by their united request, to consider his own abode there as equally determinate, if not equally indispensable.
…to believe, might have been accidentally obtained; it might not have been Edward’s gift; but a correspondence between them by letter, could subsist only under a positive engagement, could be authorised by nothing else; for a few moments, she was almost overcome—her heart sunk within her, and she could hardly stand; but exertion was indispensably necessary; and she struggled so resolutely against the oppression of her feelings, that her success was speedy, and for the time complete.
There are no more uses of "indispensable" in the book.
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Then a big pot was brought out as we raced to retrieve our indispensable spoons and bowls.
Leon Leyson -- The Boy on the Wooden Box
In fourteen years in Bluffton he had sired two sons and managed to worm his way so completely into Bennington’s life and make himself so indispensable that he sometimes seemed like Bennington’s third leg.