Means: being too curious may bring about problems for you.
Example of use: "Hey, I wonder what's down that street; it looks awfully dark and creepy." Answer: "Let's not try to find out. Curiosity killed the cat."
The origin of the idiom “curiosity killed the cat” actually lies with a slightly different idiom, “care killed the cat.” The original meaning of the word “care” as used in this instance was “sorrow” or “worry,” and both of these forms of negative emotions can cause stress that damages the body and mind.