楽しみ
たのしみ · tanoshimi · JLPT N4 · noun
pleasure
🎉 楽 (fun, ease) + しみ: the noun form of 楽しい tanoshii = fun
楽しみ is the noun built from the adjective 楽しい (fun, enjoyable): swap the final い for み and the quality becomes a thing, joy itself. The same 楽 appears in 音楽 (music). お楽しみに means look forward to it.