His whereabouts are not certain.
It is not definite whether that rumor is true.
The cause of the accident is not clear.
My memory of that time is not clear.
It is still not known whether the missing person is alive or dead.
It is not clear exactly how many people took part.
曖昧 describes something vague or ambiguous, the opposite state to what 定か (definite, certain) describes when negated.
Standard kanji spelling; commonly used in negative expressions.
Kana spelling is sometimes used for clarity or emphasis, especially in informal writing.
Derived from classical Japanese adjective 定かなり (sadakanari), meaning 'certain' or 'definite'. The modern form is almost exclusively used in negative constructions.