When it comes to describing the need for specialized expertise in a particular field or task, several synonyms can be used. Some common alternatives for "requiring specialist knowledge" include demanding specific skills, expertise-dependent, requiring specialized proficiency or know-how, necessitating specialized education, expertise-driven, and specialty-oriented. Other phrases that can convey the same meaning include requiring in-depth knowledge, needing expert-level comprehension, mandating specialized training, calling for specialized experience, and needing niche skills. Depending on the intended context and level of complexity, choosing the appropriate synonym can add depth and precision to writing, effectively conveying the required level of expertise necessary for a given task or profession.