opaque
adj.— «I’ve never run into this problem with Hotwire, though. Hotwire, like Priceline, is what’s referred to as an “opaque” travel site—meaning that certain details of your trip are withheld until you’ve booked a ticket.» —“Travel Troubleshooter: Oops, wrong airport” Miami Herald Mar. 13, 2005. (source: Double-Tongued Dictionary)