There is no specific antonym for the word "Niagaras" as it is a proper noun that refers to the Niagara Falls. However, when referring to the characteristic of "Niagaras" such as their power, force, and volume, some possible antonyms could be "weakness," "gentleness," and "quietness." In contrast to the roaring sound of the Niagara Falls, synonyms for these antonyms could be "whispering," "calm," and "soft." While the Niagara Falls is a natural wonder known for its grandeur and power, there are many peaceful and serene landscapes that offer the opposite of what the "Niagaras" represent.