The word "以此" is formed by combining two classical Chinese function words: "以", meaning "by means of" or "using", and "此", meaning "this". It functions as a compound conjunction or adverbial phrase, literally translating to "by this" or "with this", and is used to logically connect a preceding action or circumstance to a subsequent result or conclusion, meaning "therefore", "thus", or "based on this". For example, it creates a bridge in a sentence like "He studied diligently, and thereby achieved excellent results", where "以此" succinctly expresses the causal relationship.