My economics teacher actually used the word loophole but explained to us: You are allowed to use any loophole: if there is a tax break for doing x and you norm

My economics teacher actually used the word loophole but explained to us: You are allowed to use any loophole: if there is a tax break for doing x and you normally do y then you are allowed to do x to save tax. You are not allowed to lie: If you didn't do y after all you should not pretend you did.