This book describes the use of English synonyms by second language learners of English in Kenyan secondary schools. Chapter one describes the bases of the research. Chapter two introduces the pertinent issues in grammar patterns and lexical strategies related to the use of synonyms. Chapter three focuses on the research methodology. In Chapters four, five and six are the grammar patterns and the lexical strategies identified in the research. In Chapter seven the grammar patterns are correlated to the lexical strategies to reveal that the presentation of synonyms in class and in reference materials are factors that lead to inappropriate usage. The correlation also reveals that even when synonyms are presented correctly the lexical strategies the user employs lead to inappropriateness. The findings also indicate inadequate depth and width in the respondents' vocabulary. These findings are evaluated for pedagogic implications in Chapter 8, which discusses the need to investigate vocabulary teaching methods, norms and instructional materials. Chapter 9 summarizes the findings and gives recommendations for the teaching of second language vocabulary and for further research.