adj (usually not comparable) Able but not certain to happen; neither inevitable nor impossible.
adj (comparable) Capable of being done or achieved; feasible.
adj Being considered, e.g. for a position.
adj Apparently valid, likely, plausible.
n (colloquial, rare) A possible choice, notably someone being considered for a position.
n (colloquial, rare) That which is possible for somebody.
n (rare) A particular event that may happen.