The word "identicalness" refers to the state or quality of being exactly the same or similar in every detail. There are several synonyms for this word, including "sameness," "uniformity," "consistency," "unvarying," and "resemblance." These terms can be used interchangeably depending on the context of the sentence. For instance, "sameness" refers to something that has a similar or consistent nature, while "uniformity" refers to the quality of being consistent throughout. "Consistency" is an attribute of being reliable and constant in behavior or performance. "Unvarying" suggests something that does not change or fluctuate, and "resemblance" refers to the similarity in appearance or character.