noun

1. A thin and usually jagged space opened in a previously solid material.

   “A large crack had formed in the roadway.”

2. A narrow opening.

   “Open the door a crack.”

3. A sharply humorous comment; a wisecrack.

   “I didn't appreciate that crack about my hairstyle.”

Synonyms: crackpot, crack cocaine, arse, ass, bum

verb

1. To form cracks.

   “It's been so dry, the ground is starting to crack.”

2. To break apart under pressure.

   “When I tried to stand on the chair, it cracked.”

3. To become debilitated by psychological pressure.

   “Anyone would crack after being hounded like that.”