Lose

Some effects will cause artifacts, minions, and sites to lose certain abilities, often keywords. “Lose” really means "lose, can't gain, and can't have." These effects take precedence over competing passive abilities. E.g. Sky Baron wins, even if I give Wings of Invention to my minion after you summoned Sky Baron. It’s relevant to these cards:

Sisters of Silence, Silence, Entangle Terrain, Sky Baron, Atlantean Fate, Scent Hounds, Hounds of Ondaros, Master Tracker, Magnetic Muzzle, Smokestacks of Gnaak, Watchtower, Hunting Party, Sir Bors the Younger, Pebbled Paths

See the "Can vs. Can't" codex entry for more details.