adverb
not always; not necessarily; not entirely
Always used with a negative predicate (ない, とは限らない, etc.) to express that something is not universally true or does not always hold.
高いものが必ずしも良いとは限らない。
Expensive things are not necessarily good.
彼の言うことが必ずしも正しいわけでは
What he says is not always correct.