1.1 Background and Layout
Polysemy phenomenon, words that carry  different meanings,  is  quite common in any
languages, and English being not an exception.  However, in English Language, there
exists certain amount of vocabularies which convey opposite meanings itself. For example,
the word “sanction”, as a verb, can indicate both “to give permission for something to take
place” and “to punish somebody/something” (Hornby, 2009:1765), which is a paradigm of
these words usually known as antagonyms, or self-antonyms. When appeared in sentences
or passages, self-antonyms may sometimes make readers confused, were there no enough
other background information. You may  feel bewildered when seeing “plagiarism is
actually sanctioned by the government” but still cannot understand the government’s
attitude towards plagiarism.
 
Self-antonyms have been studied by scholars for a long period. Since those scholars were
from different cultural backgrounds with distinct modes of thinking, there never have been
uniformed names for self-antonyms. Some call them “antiphrasis, enantiosemy and
antimology” or simply “ambivalent words” (Dai Xiaohui， 2000:50). Others name them after
a Greek God Janus who possesses two completely different faces.  (Ma Qin，2010：112)
Other names like “reflective antonym” and “auto-antonym” have also been used. In this
thesis, the name of “self-antonyms” is adopted to express this phenomenon.
 
What’s more,  self-antonyms are not unique in English language. In China, Guo Pu first
came out with the concept that a word may carry opposite meanings in his Er Ya Zhu (《尔
雅注》)more than 1600 years before. Besides, Salim Soliman and al-Khamash has also
written 'Addad': a study of homo-polysemous opposites in Arabic (2011, 8). From examples
above, we can conclude that self-antonyms are common worldwide. In this paper, however,
we will just focus on self-antonyms in English Language.
 
The purpose of this paper is to define the origins and categories of self-antonyms. All the meanings of these vocabularies are from Oxford Advanced Learner’s English-Chinese
Dictionary, 7th
 edition (Hornby, 2009). And this paper can be briefly pided into six parts.
The first part is the introduction of self-antonyms, the objectives of this paper and research,
the methods adapted and used in the study as well as layout and arrangement of the thesis.
Then, the second part is the literature review, summarizing the studies have already done by
domestic and foreign scholars on the origins and categories of self-antonyms. Important
researches on English etymology are also contained.  The third part, the  theoretical
background, introduces the first hypothesis of this paper with examples to verify it. The
fourth part is the introduction and verification of the second hypothesis. Examples are also
provided. The last part is the conclusion part, includes the summary of the entire thesis, as
well as discusses about the social changes that causes, or reflects the opposite meanings in
self-antonyms from the perspective of other subjects including sociology and history. Major
facts contributed to the changes will also be mentioned, the conclusion will be drawn, and
the limitation of the study as well as expectations for future study around this thesis will
also be mentioned and put forward.
 
1.2 Hypotheses and Objects of Study
This paper is based on the belief that these self-antonyms must have originated from either
certain roots or affixes which carry different meanings in different languages where English
words derived from  --such as Latin, Greek and German-- which share similar spellings at 英语自我反义词的起源与分类研究(2):http://www.751com.cn/yingyu/lunwen_10477.html