relationalantonym

As an adjective slavic is

of the slavs, their culture or the branch of the indo-european language associated with them.

Relationalantonym is likely misspelled.

Relationalantonym has no English definition.

As a noun book

is a collection of sheets of paper bound together to hinge at one edge, containing printed or written material, pictures, etc.

As a verb book

is to reserve (something) for future use.