scorched earth policy

noun

1. a military practice of devastating the property and agriculture of an area before abandoning it to an advancing enemy.

noun

1. the policy in warfare of removing or destroying everything that might be useful to an invading enemy, esp by fire
2. commerce a manoeuvre by a company expecting an unwelcome takeover bid in which apparent profitability is greatly reduced by a reversible operation, such as borrowing at an exorbitant interest rate