The antonyms for the word "by names" are "unknown," "unnamed," and "anonymous." When we refer to someone by name, it means that we are using a specific and identifiable label to address them. However, when we use the antonyms of by names, we are referring to situations where the person's name is either unknown or not used. Whether due to anonymity, a lack of familiarity or simply not knowing the individual's name, using the antonyms of by names can create confusion, misunderstandings or even misidentifications in certain settings. Therefore, it is important to use accurate and appropriate language when referring to individual identities.