The opposite of "Reactive".
Often used instead of "active", which means the same thing but evidently has too few syllables.
ProActive means pseudo-active. See DilbertMoment.
Actually, no. ProActive means that when things start to go wrong, you take early, thoughtful, directed action (not just any action, and not late action) to get them back on track. While I won't support the etymology, there's a useful distinction embodied in the term.
I thought it was an active that lost its amateur status....