What are the opposite words for 100th?

The antonyms for the word "100th" are pretty straightforward. 100th represents the ordinal number of "one hundredth", so the opposite of it would be "first". Other antonyms could be "beginning", "initial", or "start". These words represent the opposite of the 100th place in a sequence. The number 100th is an important milestone, so its antonyms might not have the same significance, but they are still useful to contrast with the idea of reaching the end or reaching a goal. In conclusion, the antonyms for the word "100th" represent the beginning of a sequence or process, rather than the end.