Nevalidnost

Nevalidnost is a term used in several South Slavic languages, notably Croatian, Serbian, and Bosnian, to denote the state or quality of not being valid. The word combines ne- (not) with validnost (validity), and it is used in both formal and everyday contexts to indicate that something fails to meet required standards of validity, legitimacy, or effectiveness.

In formal logic, nevalidnost describes the lack of validity of an argument. An argument is valid when the conclusion necessarily follows from the premises; nevalidnost means there exists at least one situation in which the premises are true while the conclusion is false. It is the negation of logical validity; the term is common in explanatory or introductory discussions of logic, though technical literature often uses the term "invalid" in English.

In law and administrative contexts, nevalidnost refers to invalidity or nullity of acts, contracts, decisions, or statuses. This can arise from defects in form, capacity, consent, illegality, or violation of mandatory rules. Depending on the jurisdiction, such acts may be void ab initio (having no legal effect from the outset) or voidable (effective until annulled). The consequences typically include annulment, restoration, or exemption from legal effects.

Usage notes: the exact scope and consequences of nevalidnost vary by legal system. The term may be used synonymously with nullity or invalidity in some contexts, while in others it carries more specific procedural or doctrinal distinctions. See also validity, invalidity, nullity.