epämuotoista

Epämuotoista is a Finnish adjective used in linguistic and grammatical contexts to describe irregular or non-standard inflectional forms. The base adjective is epämuotoinen, meaning irregular or not in the normal form. In sentences, epämuotoista appears in the partitive singular, for example epämuotoista sanaa ("an irregular word"), reflecting its role as a modifier of nouns in a specific case.

The term covers words or forms that do not follow the regular Finnish inflection patterns for their part of speech. This includes some verbs with irregular conjugation, certain adjectives, and nouns whose plural or case inflection deviates from the standard paradigms. It is primarily a descriptive label used by grammarians and language descriptions rather than a fixed grammatical category for all words.

In practice, epämuotoista may be used to discuss particular irregularities, such as verb forms that fail to conform to the expected stem changes or vowel harmony rules, as well as loanwords that preserve non-standard inflections. The concept helps linguists distinguish irregular forms from the regular, predictable patterns that make up the bulk of Finnish morphology.

Etymologically, epä- is a negating prefix and muoto means form or shape; the suffix -inen turns the stem into an adjective. The form epämuotoista thus literally means "not in normal form" when describing a noun in the partitive case.