Entrench : to fix firmly or securely
Squander : waste (something, especially money or time) in a reckless and foolish manner
Extinguish : cause (a fire or light) to cease to burn or shine
Intercede : intervene on behalf of another
Defy : openly resist or refuse to obey
Oust : to eject from a position or place; force out
Hence, antonym of Entrench is Oust.