most extreme as in final, best, worst, most important, or most fundamental
The exact meaning of ultimate depends upon its context. For example:
"the ultimate decision-maker" — the final
"the ultimate car" — the best
"the ultimate insult" — the worst
"the ultimate source" — original or most fundamental
"the ultimate sacrifice" — most extreme
But, however this remonstrance might have staggered or delayed his determination, I do not suppose that it would ultimately have prevented the marriage, had it not been seconded by the assurance that I hesitated not in giving, of your sister's indifference.
Chapter 35 (48% in)
There are no more uses of "ultimate" in Pride and Prejudice.