Rigorousness is a term that describes the quality of being extremely thorough and careful in one's work or approach. Antonyms for rigorousness include laxity, leniency, and looseness.
Laxity refers to the state of being careless or lazy in one's work, while leniency suggests a more forgiving and merciful approach to tasks. Looseness can refer to a lack of structure or discipline in one's work, or a general sense of disorganization.
Other antonyms for rigorousness might include sloppiness, casualness, or nonchalance, which all suggest a more relaxed or carefree approach to work or tasks. Ultimately, the antonyms for rigorousness all suggest a less intense, less focused, or less disciplined approach to work, tasks, or life in general.