An RBG provides prediction resistance relative to time T if it provides assurance that an adversary with knowledge of the state of the RBG at some time(s) prior to T (but incapable of performing work that matches the claimed security strength of the RBG) would be unable to distinguish between observations of ideal random bitstrings and (previously unseen) bitstrings output by the RBG at or subsequent to time T. In particular, an RBG whose design allows the adversary to step forward from the initially compromised RBG state(s) to obtain knowledge of subsequent RBG states and the corresponding outputs (including the RBG state and output at time T) would not provide prediction resistance relative to time T. (Contrast with backtracking resistance.)
Sources:
NIST SP 800-90A Rev. 1 under Prediction Resistance