This study focused on the usage of the words “hard” and “difficult”. Longman Dictionary 5th edition (2009) defines the meaning of both words similarly with only slight differences. It is the problem that we, as ELS speakers, are not so familiar with this difference and might understand it differently from native speaker. It is also a problem that many ELS speakers consult dictionaries when encounter unknown words right away without understand its context. Aroonmakun (2015) states the idea that consulting English dictionaries can yield only a portal explanation for the words in questions. It appears that some researches use corpora to define word meaning and become popular lately (Ruan, 2014, Takahashi,2015). We are interested in this research method and want to examine these words thoroughly and find synonyms to avoid confusion. Webb (2007) mentions that if words with known synonyms are learned more easily than words without known synonyms, learning new words would become easier as a learner’s vocabulary size increases because more and more words are likely to have known synonyms. This study will expand into finding synonyms that is also suitable to use interchangeably with the words “hard” and “difficult” in different contexts.