The word "lengthinesses" refers to long, tedious stretches of time or descriptions. However, there are several antonyms for this word that indicate brevity, conciseness, or simplicity. Some possible antonyms include "conciseness," "brevity," "succinctness," "terse," "pithiness," "clarity," "simplicity," "directness," "uncomplicated," "shortness," and "abridgment." These words describe qualities that are desirable when communicating ideas or information quickly and effectively. When used in contrast to "lengthinesses," they indicate a preference for clear, concise, and efficient communication that gets straight to the point. By using these antonyms, speakers or writers can signal their intention to be brief and direct in their communication.