terapeuttin
Terapeuttin is not a standard Finnish noun. In Finnish, the term for a professional who provides therapeutic services is terapeutti, and the genitive (possessive) form is terapeutin. The sequence terapeuttin can appear in some texts as a misspelling or nonstandard variant, but it is not recognized as a correct inflection of terapeutti in contemporary Finnish grammar.
Etymology and equivalents: The Finnish terapeutti is a learned borrowing that traces back through European languages
Usage and note: Because terapeutin is not standard Finnish, it is generally avoided in formal writing. When
See also: Therapist, Therapy, Therapeutic, Therapeutics.
In summary, terapiettin is not part of standard Finnish, and terapeutti with the genitive terapeutin is the