[InclinedPlane]

Neutrinos conclusively have mass since they experience flavor oscillations (if they were massless that would be impossible). Current estimates are that the total mass of all flavors of neutrinos is a fraction of 1 eV (less than a billionth the mass of a proton).

Anyway, neutrinos aren't generally called "WIMPs" because they already have a name, the term "WIMP" is generally reserved for new particles that have yet to be directly observed.

[geon]

Does the "massive" in WIMP mean "have a mass" or "higher mass than other particles"?

[InclinedPlane]

It means it has non-zero mass. There are some theories of dark matter which would involve particles having thousands of times less mass than even a neutrino.