reageerinud

Reageerinud is an Estonian word that functions as the past active participle of the verb reageerida, meaning to react or to respond. It designates a subject that has already performed the action of reacting to something. The form is formed from the verb stem reageeri- with the participial suffix -inud, yielding reageerinud. Like other Estonian participles, reageerinud can agree with the noun it describes in number and case when used attributively and can appear in non-finite clauses or in combination with auxiliary verbs.

In usage, reageerinud is most commonly seen in perfect tense constructions with the auxiliary olema, as in on reageerinud, meaning has or have reacted. It can also function as a non-finite adjective in clauses that describe a participant who has already performed an act of reacting, for example in relative clauses introduced by kes on reageerinud (the person who has reacted). The word is standard language—not dialectal or slang—and is part of ordinary Estonian grammar.

Etymology and related forms: reageerinud is derived from the verb reageerida. The participial suffix -inud marks the past active participle for this class of verbs, and the form follows general Estonian rules for participles, including agreement with modifiers and compatibility with tense constructions.

See also: reageerida; past participles in Estonian; Estonian grammar.