We propose a method "Interactive Paraphrasing" which enables users to interactively paraphrase words in a document by their definitions, making use of syntactic annotation and word sense annotation. Syntactic annotation is used for managing smooth integration of word sense definitions into the original document, and word sense annotation for retrieving the correct word sense definition for a word in a document. In this way, documents can be paraphrased so that they fit into the original context, preserving the semantics and improving the readability at the same time. No extra layer (window) is necessary for showing the word sense definition as in conventional methods, and other natural language processing techniques such as summarization, translation, and voice synthesis can be easily applied to the results.