sairastui

Sairastui is the past tense form of the Finnish verb sairastua, meaning to fall ill or to become sick. It is an intransitive verb used to describe the onset of an illness. The form shows that the subject became ill in the past.

In everyday use, sairastui pairs with a subject and often stands alone or with a phrase indicating the illness: for example, Hän sairastui viime viikolla (He fell ill last week). It can also be used with the illative case to specify the illness, such as sairastua flunssaan (to come down with the flu) or sairastua keuhkokuumeeseen (to come down with pneumonia).

Conjugation around sairastua follows regular Finnish verb patterns for past tense forms: minä sairastuin, sinä sairastuit, hän sairastui, me sairastuimme, te sairastuitte, he sairastuivat. This distinguishes it from the related verb sairastaa, which is transitive and commonly means to suffer from or to have an illness, with past tense forms such as sairasti.

Etymology wise, sairastua is built from sairas (ill) plus the -stua suffix, forming a verb that denotes the process of becoming ill. The noun sairaus, meaning illness, is related and frequently appears in discussions of health and disease in Finnish.

See also: sairastaa, sairaus, tauti, terveys.