Derivational affixes are not always automatically classified into functional or lexical categories. Although they are treated differently in various approaches, a shared view contends that the status of a suffix is controversial when it forms categorially incoherent words. However, it is debatable even when it forms words of a single category. This study argues that the Bifurcated Lexical Model proposed by Joseph E. Emonds is promising in this respect. With two subcomponents of the lexicon that, respectively, store functional and lexical morphemes, the model allows an affix to behave both as a functional and a lexical morpheme. This study demonstrates that the model can successfully account for the properties of the deverbal noun-forming suffix -ment in Present-Day English. The -ment nouns newly retrieved from the Oxford English Dictionary Online include instances in which -ment attaches to non-verbal elements and converted words. While such nouns may pose potential challenges to the perspective of an affix as a functional morpheme, their existence is not surprising but rather predictable within the model that allows for the flexibility of an affix in the dichotomy between functional and lexical categories.