not necessarily
Not definitely or always; possibly not. Because of the different income tax brackets here, a higher wage isn't necessarily a good thing, as you may end up paying more than you were before. A: "Based on this evidence, he's definitely guilty." B: "Not necessarily. There are lot of factors that still need to be considered."
ˌnot necesˈsarily
used to say that something is possibly true but not definitely or always true: The more expensive articles are not necessarily better.Biggest doesn’t necessarily mean best.(spoken) ‘We’re going to lose.’ ‘Not necessarily.’