Finnish word luulosairaus comes from Finnish sairaus (Sickness, illness, malady, disease, ailment.), Finnish luulo

Detailed word origin of luulosairaus

Dictionary entry	Language	Definition
sairaus	Finnish (fin)	Sickness, illness, malady, disease, ailment.
luulo	Finnish (fin)	Belief, thought, impression, especially a wrong or misled one.
luulosairaus	Finnish (fin)	(colloquial) hypochondriasis.