An proactive person takes action before things happen, they don't wait for situations to come up.
Imagine you're planning a party. A reactive person would only start organizing when the guest list is due or the date is near. But an proactive person would think ahead and send out invitations early, make a budget, and book a venue weeks in advance. They'd also be thinking about what games to play, decorations to buy, and food to prepare. By taking charge and planning ahead, they can avoid last-minute stress and make the party run smoothly.
Note that some people might use "proactive" specifically to describe someone who solves problems before they become big issues, or anticipates potential risks in their work or life. But in general, being proactive just means thinking ahead and acting on what you need to do to stay one step ahead.
Acting in advance to deal with an expected change or difficulty.
Example: We can deal with each problem as it pops up, or we can take a proactive stance and try to prevent future problems.
