1 (usually the slammer) informal prison:if he had lived, he’d be in the slammer today
2chiefly North American a person who deliberately collides with others when slam-dancing:a bit further back the slammers and bashers danced, shoved, tussled
3 (also tequila slammer) a cocktail made with tequila and champagne or another fizzy drink, which is covered, slammed on the table, and then drunk in one.
slammer in other Oxford dictionaries
Definition of slammer in the US English dictionary