"Efficient" and "useful" are two synonyms for the word "noteful". When something is considered "noteful", it means that it is helpful and beneficial in some way. By using the synonym "efficient", we emphasize the ability of an object or action to produce the desired result quickly and with minimal effort. On the other hand, the synonym "useful" highlights the practicality and advantage of the item or activity. Whether we use "efficient" or "useful" instead of "noteful", the underlying meaning remains the same – something that aids or assists in a beneficial manner.