Oyster
.Fast as a Kentish oyster, i.e. hermetically sealed. Kentish oysters are proverbially good, and all good oysters are fast closed.
· 
· 
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Entry taken from Dictionary of Phrase and Fable, edited by the Rev. E. Cobham Brewer, LL.D. and revised in 1895.