äisiintaisiin
Äisiintaisiin is a term that appears in early 20th-century Finnish literature, notably in the works of Ilmari Kianto. It is believed to be a dialectal word, possibly from the Kainuu region, and its exact meaning is somewhat debated among scholars. Generally, it is understood to describe a state of being deeply affected, often by an overwhelming emotion, or a profound, sometimes unsettling, realization.
The word seems to carry connotations of being struck by something significant, whether it be a sudden
Linguistic analysis suggests a possible connection to older Finnish words related to astonishment or being struck.