• above board, aboveboard, candid, direct, disarming, explicit, express, flat, forthright, frank, free, genuine, honest, ingenuous, outright, outspoken, overt, point-blank, pointed, round, sincere, straightaway, straightforward, transparent, unconcealed, unconfused, undisguised, up front, upfront
• aperture, break, crack, gap, hatchway, hiatus, mouth, muzzle, opening, port, recess, slit, slot, spread, throat, vent
• blue sea, blue water, high sea, high seas, open sea, open seas
• in the open sea, offshore