Parsing algorithm that operates top-down, starting with the start symbol, and predicting or guessing which grammar rule to used to rewrite the current sentential form.
Alternative grammar rules are stacked so that they can be explored (using backtracking) if the current sequences of guesses turns out to be wrong.
On general context-free grammars, a vanilla predictive parser takes exponential parsing time (i.e. it can be very very slow). See also bottom-up parsers.