The word "de tains" is not very common and does not have any specific antonyms. This is because it is not a recognized word in the English language. It is possible that it may be a misspelling of the word "detains" which means to keep someone in custody or to prevent them from leaving. The antonym for this word would be "release" or "free". Another possibility is that "de tains" is a combination of two words "de" meaning "of" or "from" and "tains" which is not a recognizable word. In this case, the antonyms for "de" and "tains" would depend on the context in which they are used.