käsitsemist
Käsitsemist is not a standard Finnish word found in authoritative dictionaries. It appears to be a nonstandard form, likely a misspelling or typographical error related to the Finnish verbs and nouns around handling, processing, or treating.
The Finnish language normally uses several related terms for these concepts. The noun käsittely denotes handling,
In practice, Finnish writers would choose between käsittely and käsitteleminen based on nuance and register. Käsittely
If you encounter käsitsemist in a text, it is likely a typo or OCR error. To determine