I would nominate "reckless".
The answer is slapdash
The opposite would be sudden or abrupt, so the adjective could be hurried or instant.
A four letter word meaning not kosher is: tref
What is a nine letter word meaning very tidy
The word pine can have that meaning.
The answer is slapdash
Hustled or bustled.
a stupid or careless mistake
hurried
litterbugs
Careless and reckless are synonyms for irresponsible. Immature is another synonym.
The word meaning in a lax or careless manner is spelled "lackadaisical".
The phrase "rehna bindas" in Hindi means to live carefree or without worries. It conveys the idea of staying relaxed, being oneself, and enjoying life without any stress or fear.
careless or carelessly; impulsive; mechanical
With the word meaning "primary or most important": This is the chief cause of the incident. With the word meaning "the head of a department": The chief of police hurried with the officers to the scene.
Untidy or haphazard, careless vs. careful. messy
I hurried my responses to finish the test within the time limits. The patrol hurried and harried the fleeing attackers. It was obvious the response was hurried.