Abstract Conversion has been sometimes claimed to be a common occurrence in Chinese, as e.g. piàoliang ‘pretty’ → ‘prettiness’ (Steffen Chung 2014). However, the application of the notion of conversion to Chinese poses several challenges, related to the (isolating/analytical) morphological profile of the language, and to how word classes are defined and attributed to individual words. In this chapter, after an overview of word-formation in Chinese, the nature of word classes in the Chinese lexicon will be clarified, showing that there is a considerable degree of categorial ambiguity, with several competing analyses on the very nature of the system of lexical categories in this language (Basciano 2017). The chapter will present various cases of items which behave as different word classes, distinguishing mainly between instances of regular ambiguity (lǐngdǎo ‘leader’, ‘lead’) and of innovative ambiguity (xiǎochǒu ‘clown’, ‘clownish’; Kwong and Tsou 2003). It will be argued that the latter resemble more prototypical conversion, whereas for the former it is hard to argue for a direction in the process.