speculator

verb | \ ˈspe-kyə-ˌlāt \ | spec·u·late

1. : to theorize on the basis of insufficient evidence

   Note: A jury is not permitted to speculate on a matter about which insufficient evidence has been presented in reaching its verdict.

2. : to assume a business risk in hope of gain; especially : to buy or sell in expectation of profiting from market fluctuations : to buy or sell in expectation of profiting from market fluctuations

   : to take to be true on the basis of insufficient evidence