Rationaalset

Rationaalset is the partitive singular form of the Estonian adjective rationaalne, meaning rational. It is used when describing a noun that appears in the partitive case, or in constructions that express an indefinite quantity or focus on the concept rather than a definite noun. As a grammatical form, it does not carry a separate lexical entry; dictionaries list rationaalne and its inflected forms, including rationaalset, as part of the same word.

Typical contexts include phrases such as rationaalset mõtlemist (rational thinking), rationaalsetel põhjustel (for rational reasons), and rationaalset lähenemist (a rational approach). The form also appears with nouns in various cases when the dependent adjective is marked for partitive singular, though it is most common in object or complement positions. In other grammatical contexts, other inflected forms of the adjective are used, such as rationaalne (nominative), rationaalse (genitive/dative), and so on.

Rationaalne is a standard Estonian adjective denoting rationality in logic, reasoning, or behavior. The partitive form rationaalset is produced by ordinary Estonian agreement and case rules for adjectives. The word is formed from the root ration- with the suffix -aalne and is then declined to match the case and number of the noun it modifies.

See also: rationaalne, rationality, rationalism, Estonian grammar.