That question contradicts itself, given how I just defined "judicial activism".
You're assuming that everyone knows the "true meaning" of some disputed part of the Constitution. Those that know the true meaning yet go against it are enganging in judicial activism. Those that want to stay with the meaning are strict constuctionists.
I say it's not that black and white. I say that there are people (and judges) who believe the true meaning of some part of the Constitution is totally opposite of what you and I believe. Who, then, is the activist? Who, then, is the strict constructionist?