Active: An active listing in MLS theoretically means the listing should still be available. However, the Honolulu Board of Realtors is somewhat liberal in allowing 4 days from when an offer is accepted to change the status to either "Active Continue to Show" or "Pending" in MLS
Active Under Contract: If a listing says "Active Under Contract", it means the Seller has accepted an offer on their property. It also says that the Seller will continue to show it for backup offers. Most agents keep a listing in this status until the Buyer has removed most of their contingencies (ie. home inspection, financing, etc.). It is however subjective on the agent's behalf as to when they change a status to "Pending" instead of "Active Under Contract". Most pending status listings to not show up IDX websites.
One of the (many) advantages of searching for a property on this site is we give the consumer access to see whether or not a property is Active or Active Under Contract in the Status field of a property's detail page. We still recommend it is always best to check with your Realtor to see what the true status is of a listing.