Eským

Eským is the instrumental singular masculine form of the Czech adjective eský. In Czech, adjectives decline to agree with the nouns they modify, and eský follows the same pattern as other -ský adjectives. When used with a masculine singular noun in the instrumental case, the ending changes to eským (for example, the form that would appear before a masculine noun in instrumental position). The stem remains esk-, with the ending adjusted to -ským in the instrumental.

The instrumental case in Czech expresses means, manner, or means by which an action is performed, among other functions. Therefore, eským would appear in phrases where an adjective explains a noun functioning in instrumental contexts, such as describing the means or manner associated with the noun. It is part of standard Czech adjective declension, although eský itself is far less common in contemporary usage than more widely used adjectives such as český (Czech) or slovenský (Slovak).

Historically, the -ský family of adjectives is productive in Czech and forms many ethnonyms, toponyms, and descriptors of relation or origin. The specific form eským is simply the regular instrumental singular masculine ending for this class of adjectives. Because eský is not a frequent word in modern Czech outside specialized or historical contexts, eským is encountered mainly in grammars or examples illustrating standard noun–adjective agreement rather than in everyday prose.

See also: Czech grammar, adjective declension, instrumental case.