The word "stick-to-itiveness" refers to the quality of perseverance and determination in achieving a goal. Its antonyms include words such as disinterest, apathy, and indifference - all of which describe a lack of motivation, drive, or ambition. Other antonyms include words like inconstancy, fickleness, and wavering, which describe the opposite of steadfastness and commitment. When someone lacks stick-to-itiveness, they may give up easily, lack the discipline to see things through, or lose focus easily. Therefore, it is crucial to cultivate a trait of determination and persistence, rather than giving in to negativity and complacency.