(1) In orienteering, to deliberately aim to one side of a feature so that you definitely know which way to turn when you get near it.
(2) Used when following a compass bearing.
Aiming off is like deliberately missing a target.
You probably won't hit the bullseye no matter how hard you try. Honestly. You're not that good.
So if you go ahead and aim for it anyway because you're ornery, you will still miss. You're really, seriously not that good. We've seen you, and it's obvious. But aiming off can make you seem smart. So smart that people will finally pretend to respect you, so listen up.
With aiming off you secretly make your target much bigger and then deliberately miss to one side.
That's step one, and any fool can do it, even you. Step two is even easier.
Step Two: You know you missed your bullseye to one side, and which side that was, so you know how to correct for your mistake. So you do. Bingo. You can suddenly navigate like Columbus.
Example: Say you want to get back to camp, which is by a river. If you aim for your tent and come to the river without seeing the tent, then you have no idea which way to go from there, or how far.
But if you deliberately aim upstream then you know that when you get to the river you have to go downstream from there. Maybe not how far, but you know your tent is definitely downstream.
You will look like a genius.
You can't lose.
Unless the normal error in walking (which will knock you off course about three to five degrees), coupled with your natural incompetence (could be huge), lumpy ground, annoying large trees, and general woodland untidiness conspire to actually take you somewhere else entirely.
Or someone steals your tent while you're out mooning around.
Then when you confidently turn to walk that last short leg directly to your tent (where your tasty food and fresh puffy sleeping bag should be expectantly waiting for you), you will in reality be sailing blindly off into the outer darkness and will die a miserable and lonely death in the cold.
Poor you. What a dope. Maybe you should just stay home and watch TV.
Remember Columbus? The guy who aimed at Asia and missed?