Definition of unprosperity in English:
unprosperity
noun (ˌ)ʌnprəˈspɛrɪti(ˌ)ʌnprɒˈspɛrɪti
rare Lack of prosperity; an instance of this.
Origin
Early 17th century; earliest use found in Fulke Greville (1554–1628), courtier and author. From un- + prosperity.