crack·er 
/ˈkrækɚ/ noun
plural crack·ers /ˈkrækɚ/ noun [count] 1 : a dry, thin baked food that is made of flour and water and is often eaten with cheese
▪ a plate of cheese and crackers — see also animal cracker, graham cracker, oyster cracker, soda cracker 2 : a person who can crack something (such as a safe or a secret code)
▪ a safe cracker [=a criminal who can opens a safe illegally] ▪ a code cracker 3 chiefly Brit : a colorful paper tube that holds small gifts and that opens with a loud noise when the ends are pulled ◊Crackers are commonly used in Britain at Christmas.
▪ a Christmas cracker 4 Brit, informal : a very good, amusing, or attractive person or thing
▪ The match should be real cracker. ▪ The guitarist played a cracker of a solo. 5 US, informal + offensive : a poor usually Southern white person
▪ a plate of cheese and crackers — see also animal cracker, graham cracker, oyster cracker, soda cracker
▪ a safe cracker [=a criminal who can opens a safe illegally] ▪ a code cracker
▪ a Christmas cracker
▪ The match should be real cracker. ▪ The guitarist played a cracker of a solo.
