The thief tried to use a hostage as a 'human shield'. [=the thief hid behind the hostage so the police would not shoot]
Exercise and good nutrition are a 'shield against' disease. [=exercise and good nutrition protect you from disease]
I think she's 'shielded' her child 'from' the real world for too long.
(..) You just came up with that? Maester Aemon said it a long time ago. Sometimes duty is the death of love. You are the shield that guards the realms of men. And you've always tried to do the right thing. No matter the cost, you've tried to protect people. (..)2019 TvShow: Game of Thrones Title: The Iron Throne Season: 8 Episode 6