和制英语是日语词汇的一种，利用英语单字拼合出英语本身没有的新词义。

「和制英语」一字，只适用于表示从英语单字创造出来的词语；从其他欧美地区语言单字所创造出来的词语，则会使用“和制外来语”一字表示。

一些与英语单字本身意思不同地使用（即误用），或者把动词错误地作名词般和其他单字组合的误用，甚至把单字作日式简略后发音的词语等等，广义上来说也可被包含在和制英语范围之内。

如果只是在日语用户之间使用和制英语的话，一般并不会引起不必要的误解。但是却会因此而把本来的英语表现误用、误认，所以经常令一些学习日语的英语用户感到困惑。同样情况亦出现于本来源自英语以外语言（法语及德语等）的词语，却被误以为是来自英语的和制外来语身上。

The term Wasei-eigo(和製英語, "Japanese-made English", "English words coined in Japan") refers to Japanese language expressions which superficially appear to come from English, but in fact do not. These words were originally borrowed loanwords deriving from English but have become so embedded into the Japanese lexicon that they are re-fashioned to create a novel meaning – diverging from its original intended meaning. An example of wasei-eigo is reberu appu(レベルアップ,'level up'), which means "raise a level", the preposition being interpreted in line with Japanese word order as a verb qualifying its preceding object). Some wasei-eigo terms are not recognizable as English words in English-speaking countries, such as sukinshippu(スキンシップ,'skinship'), which refers to physical contact and appears to have been coined from skin and kinship. In other cases, a word may simply have gained a slightly different meaning; kanningu(カンニング) means not "cunning", but "cheating."