unsubstantiated
UK: ˌʌnsəbˈstænʃieɪtɪd | US: ˌʌnsəbˈstænʃieɪtɪd
adj. not supported or proven by evidence
adj. lacking factual basis; speculative
The word "unsubstantiated" combines the negative prefix "un-" (Old English "un-," meaning "not") with the root "substantiate," derived from Latin "substantia" (substance, essence). The suffix "-ate" forms a verb meaning "to make or prove," and "-ed" turns it into an adjective. Literally, it means "not made into substance"—i.e., lacking proof or solid foundation. The term reflects a logical progression from physical substance (Latin "substantia") to abstract verification.
The journalist's claims were dismissed as unsubstantiated rumors.
Without data, your argument remains unsubstantiated.
The court rejected the unsubstantiated allegations.
Her theory was interesting but entirely unsubstantiated.
Unsubstantiated fears often lead to unnecessary panic.