1. (

• crack ,
• check ,
• break ,

) become fractured; break or crack on the surface only; "The glass cracked when it was heated" ;

2. (

• crack ,

) make a very sharp explosive sound; "His gun cracked" ;

3. (

• snap ,
• crack

) make a sharp sound; "his fingers snapped" ;

4. (

• crack

) hit forcefully; deal a hard blow, making a cracking noise; "The teacher cracked him across the face with a ruler" ;

5. (

• break_through ,
• crack ,

) pass through (a barrier); "Registrations cracked through the 30,000 mark in the county" ;

6. (

• crack ,

) break partially but keep its integrity; "The glass cracked" ;

7. (

• snap ,
• crack

) break suddenly and abruptly, as under tension; "The pipe snapped" ;

8. (

• crack

) gain unauthorized access computers with malicious intentions; "she cracked my password"; "crack a safe" ;

9. (

• crack_up ,
• crack ,
• crock_up ,
• break_up ,
• collapse

) suffer a nervous breakdown ;

10. (

• crack

) tell spontaneously; "crack a joke" ;

11. (

• crack ,

) cause to become cracked; "heat and light cracked the back of the leather chair" ;

12. (

• crack ,

) reduce (petroleum) to a simpler compound by cracking ;

13. (

• crack ,

) break into simpler molecules by means of heat; "The petroleum cracked" ;

1. (

• chapped ,
• cracked ,
• roughened

) used of skin roughened as a result of cold or exposure; "chapped lips" ;

2. (

• alligatored ,
• cracked ,

) of paint or varnish; having the appearance of alligator hide ;

3. (

• balmy ,
• barmy ,
• bats ,
• batty ,
• bonkers ,
• buggy ,
• cracked ,
• crackers ,
• daft ,
• dotty ,
• fruity ,
• haywire ,
• kooky ,
• kookie ,
• loco ,
• loony ,
• loopy ,
• nuts ,
• nutty ,
• round_the_bend ,
• around_the_bend ,
• wacky ,
• whacky

) informal or slang terms for mentally irregular; "it used to drive my husband balmy" ;