reckless
adj.adj. doing something dangerous without thinking about what might happen. You use this to describe someone who takes risks that could hurt themselves or others.
adj. acting or done without regard to the consequences or danger of an action. Often used in legal or formal contexts to describe a lack of caution that endangers others.
He was arrested for reckless driving on the highway.
The company faced heavy fines after a reckless decision to ignore safety warnings led to a chemical leak.
The historian argued that the general's reckless pursuit of glory ultimately cost him the loyalty of his troops and the stability of the empire.
From Middle English rekles, reckeles, rekkeles, (also recheles), from Old English rēcelēas (“reckless, careless, negligent”), equivalent to reck + -less. Cognate with West Frisian roekeleas (“reckless”), Dutch roekeloos (“reckless”), German Low German ruuklos (“careless”), German ruchlos (“careless, notorious”).
Typically precedes the noun it modifies or follows a linking verb like 'be' or 'become'.