To break or cause to break without complete separation of the parts. The ice began to crack under the weight of the skater.
To solve or decipher a difficult problem or code. The detective managed to crack the case after weeks of investigation.
To make a sudden, sharp noise. He cracked his knuckles loudly before starting the exam.
To lose control of one's emotions or mental state. Under the intense pressure, she finally cracked and started to cry.
To open something slightly. She cracked the window to let in some fresh air.
To strike someone or something sharply, often producing a sound. He cracked the ball with his bat, sending it over the fence.