| verb | become fractured; break or crack on the surface only “The glass cracked when it was heated” |
| verb | make a very sharp explosive sound “His gun cracked” |
| verb | make a sharp sound “his fingers snapped” |
| verb | hit forcefully; deal a hard blow, making a cracking noise “The teacher cracked him across the face with a ruler” |
| verb | pass through (a barrier) “Registrations cracked through the 30,000 mark in the county” |
| verb | break partially but keep its integrity “The glass cracked” |
| verb | break suddenly and abruptly, as under tension “The pipe snapped” |
| verb | gain unauthorized access computers with malicious intentions “she cracked my password” |
| verb | suffer a nervous breakdown |
| verb | tell spontaneously “crack a joke” |
| verb | cause to become cracked “heat and light cracked the back of the leather chair” |
| verb | reduce (petroleum) to a simpler compound by cracking |
| verb | break into simpler molecules by means of heat “The petroleum cracked” |
| adjective | used of skin roughened as a result of cold or exposure “chapped lips” |
| adjective | of paint or varnish; having the appearance of alligator hide |
| adjective | informal or slang terms for mentally irregular “it used to drive my husband balmy” |
| check | noun | a mark left after a small piece has been chopped or broken off of something |
| breakable | adjective | capable of being broken or damaged |
| break | noun | breaking of hard tissue such as bone |
| cracker | noun | firework consisting of a small explosive charge and fuse in a heavy paper casing |
| cracking | noun | a sudden sharp noise |
| snap | noun | the act of snapping the fingers; movement of a finger from the tip to the base of the thumb on the same hand |
| crack | noun | a long narrow opening |
| crack-up | noun | a mental or physical breakdown |
| collapse | noun | an abrupt failure of function or complete physical exhaustion |
| daftness | noun | informal terms for insanity |
| kook | noun | someone regarded as eccentric or crazy and standing out from a group |
| loon | noun | a person with confused ideas; incapable of serious thought |