1. To act in reckless disregard.
2. A form of permission.
3. A suggested course of action.
"Give'er Terry, give'er, give'er, give'er!"
This will work if:
1. Terry is about to do something reckless and is being egged on by friends who are encouraging him to continue/begin this action regardless of the consequences.
2. Terry asks if he can get a beer from the fridge. (typically reduced to one "give'er" instead of the above multiple "give'er's"
3. Terry asks you if its a good idea to ask out that good looking woman he sees.
When all else fails, when mere brute force is not enough, it is time to grit your teeth and GIVE 'ER.
GIVE 'ER can apply to anything from jamming the throttle on your big block wide-open to you and the boys putting a bit of muscle into whatever misguided task you've drunkenly committed to.
GIVE 'ER can be applied to nearly any situation where finesse is no longer a viable option.
You'll probably never get that Audi stuck in snow with those Hakkas on it, but if you really, really bottom it out on sheer ice or some s--t, I say just DROP TEH CLUTCH AND GIVE 'ER.