明 らか and 明 白
明らか: neutral, for conversation and writing
明白: more polite, usually used for writing
https://hinative.com/ja/questions/354061
田 , 水 田 , and 田 んぼ
- 田圃 is usually written in 田んぼ or たんぼ, and it’s the word usually used in conversations.
- 水田 is a Sino-Japanese word (漢語), and it sounds more technical/formal. You will find 水田 in official documents, scientific articles, and such.
- 田 is not a word commonly used in isolation in sentences (at least in modern standard Japanese). In most cases it appears in compound words such as 水田, 田園, 田畑 and 田植え.
In some dictionaries, 水田 seems to be defined as something like “田 filled with water”, as if dry 田んぼ were not 水田. IMHO you can ignore this definition and think 水田 almost always just means “rice field”.