Streng is a German word that translates to "strict" or "severe" in English. There are several synonyms that could be used interchangeably with the word streng, depending on the context in which the word is used. Some possible options include "rigorous," "stringent," "exact," and "demanding." Additionally, the words "harsh," "cruel," and "oppressive" may be used to indicate an even stronger level of severity or strictness. In some cases, the synonyms for streng might carry slightly different connotations or implications, so it's important to choose the best word based on the specific tone and meaning intended for the sentence or phrase.