The word "in appreciably" means something that cannot be easily perceived or noticed. Its antonyms include words such as significantly, perceptibly, markedly, noticeably, appreciatively, and substantially. These words convey the opposite meaning of "in appreciably" and indicate something that is noticeable, important or significant. For instance, if someone were to say that there was an "in appreciable" change in the performance of a football team, this would mean that there wasn't much difference. However, if they said there was a "significant" change, it would indicate that something significant had happened. In conclusion, understanding the antonyms of a word can help you better understand its meaning in context.