What word describes acting or reacting with a lack of consideration for consequences?

The term that describes acting or reacting with a lack of consideration for consequences is "impulsive." When someone is impulsive, they tend to make decisions or take actions quickly without fully thinking through the potential outcomes. This behavior often leads to unexpected results because the individual is focused on immediate gratification or reaction rather than weighing the long-term effects of their actions.

In contrast, other terms such as "prudent," "rational," and "calculating" imply a more measured and thoughtful approach to decision-making. For instance, being prudent means exercising good judgment and foreseeing potential risks, while being rational involves using logic and reason to guide decisions. The word "calculating" suggests a strategic and deliberate approach, often with an intent to maximize benefits or minimize losses, which inherently contrasts with the spontaneous nature associated with impulsivity.