英和和英

an unnamed donor

an unidentified witness

an unknown source

destination unknown

an ineligible pass receiver

unknown in advance

not openly acknowledged

an unknown quantity

anonymous

not informed

in a manner that is unclear

unknown to most people

without awareness

people who have not confessed

an unknown number

an unknown quantity

haven't/hasn't received …

Some passages are obscure in meaning.

not recognized

an unknown amount

an unliveried chauffeur

not assigned

without someone's knowledge

an unidentified species

not correspondent

His whereabouts is unknown

He is missing.

not chartered

a period of time during which something is secret

an unidentified ship