A neophyte refers to a beginner or someone who is new to a particular skill, field, or activity. It implies a lack of experience or knowledge in the given area. In this context, the word "neophyte" fits the description of a beginner, which is consistent with the given clue "a beginner." The other options, such as petrify, vagrant, sullen, and emissary, do not convey the same meaning and are unrelated to the concept of being a beginner.