Ranked by relevance and common usage.
Keep "illimitably" when the sentence already sounds natural, when a synonym would add unintended emphasis, or when readers need the most familiar wording. A synonym should clarify or sharpen the message, not simply make the sentence look more varied.
If two options seem close, choose the one that best matches the audience and purpose of the sentence.
Choose a synonym only if it keeps the core idea of "illimitably" intact in the sentence you are editing.
Check whether the replacement sounds more formal, casual, emotional, technical, or forceful than the original word.
Read the full sentence after the swap. Keep the synonym only when the sentence becomes clearer or more precise.
Review note: Synonym lists are ranked with lexical data and reviewed for practical writing value. Use the comparison notes, sentence evidence, and source labels together; a high-ranking synonym can still be wrong when the audience, register, or grammar changes.
After choosing a replacement for "illimitably", read the sentence once for meaning and once for rhythm. The best synonym should feel natural in the full sentence, not only accurate in a word list.
If the synonym makes the sentence slower, vaguer, or more dramatic than intended, keep "illimitably" or choose a simpler alternative from the closest-match group.
3 total sentences available.
Over all these ascends, at the distance of twenty five miles, the round summit of Agamenticus. North-eastward, the Isles of Shoals appear, at the distance of eight leagues, like a cloud in the horizon. Eastward, the ocean spreads illimitably.
Source: wiktionary
We are glad to perceive that premature efforts are not made to accomplish what cannot be done well for, though the art is illimitably long, yet a slow progress is the most sure, and will ultimately be found the most rapid. The taste of the public, too, cannot be forced; but must be carried gradually and easily along to the highest branches of the art, or it will fall back again to the rude and unformed state from which it is just emerging.
Source: wiktionary
The wind had scattered every cloud, and still howled through the clear gray morning sky, the sea was in violent commotion, and huge surges broke heavily and rapidly on the beach. The tide was flowing fast, and the bed of the river, we had crossed so safely the night before, was covered by the waves; in a little time the ford would be impassable, and this was another reason to hasten the arrival of the horses. To the east each crag and precipice, each vast mountain top, showed in dark relief against the golden eastern sky; seaward the horizon was misty from the gale, and the ocean stretched out illimitably; curlews and gulls screamed as they skimmed the crested waves, and breaker after breaker dashed furiously at my feet.
Source: wiktionary
Closest matches include ad infinitum, endlessly, eternally, forever, immeasurably.
Compare the replacement against real sentence context. This entry includes sample sentences so you can check tone, grammar, and meaning before swapping words.