Reckless means showing a lack of care for the consequences of one's actions; rash or heedless.
Here are some synonyms for reckless:
* Careless
* Imprudent
* Rash
* Heedless
* Irresponsible
* Negligent
Here are some examples of how "reckless" is used:
* "He drove his car at reckless speed."
* "Her reckless spending habits got her into debt."
* "The company's reckless environmental practices have had a devastating impact."