The fourteen disyllabic words"X 而"in the 7 th edition of The Contemporary Chinese Dictionary are all formed by the lexicalization of syntactic sequences.Some of these words can be classified as conjunctions or adverbs,while others might change between those two types or become conversion words.Through an investigation of the lexicalization process of"X 而"disyllabic words,this paper finds that the degree of semantic change of the morpheme"X"is highly correlated with their part-of-speech classification.The degree of semantic bleaching of"X"from the initial stage to the transitional stage,as well as the difference in semantic features between"X"and"X 而"from the transitional stage to the word-formation stage,jointly determine the part-of-speech classification of"X 而"disyllabic words.