I love this phrase, although I cringe when using it; it seems a bit brusque. To me it means "go right ahead and do it, even though there’s not much use in your effort"
Do any of you use it?
I do use it on occasion, and surprisingly enough, I have some thoughts about it.
First, to me it implies the giving of permssion to a person to expend all effort, even to the point that unconsciousness results, to accomplish some task that the person has asked to do. I offer the following scenario:
You visit the home of a friend. You ring the doorbell and your friend’s teenage son opens the door. "Come in" he says, turns away from the door and yells "hey Dad, your friend, what’s his name is here", and then plops himself down on the most comfortable chair in the living room and resumes watching MTV. "May I sit down?" you ask. "Knock yourself out", he says. As you move to the sofa you fail to see the cord stretching accross the floor to a steel guitar leaning against the far wall. You trip over the cord and bang your head on an end table. You have successfully knocked yourself out in the attempt to accomplish the task of sitting down.
As I see it, the phrase, "knock yourself out" can be taken as insolence, or friendly invitation, depending on the context.
I offer the following example for the first case:
Your wife says something like "if you don’t _______"(fill in the blank), "then I’m going to _______" (fill in the blank).
You say, "knock yourself out".
No, wait, that’s not a good example. It is not the wife who will be knocked out in this case.
But the following example might work in the second case:
Your cousin has just bought his sixth Ferrari of the year (it is June after all, and he is after all, an American, living in the wealthiest country of the world where even the poorest of the poor can afford at least a two year old Mercedes). You say, "Hey, Cuz, can I take your Ferrari and your girlfriend for a spin? My Mercedes is in the shop."
"Knock yourself out", he replies, meaning "be my guest, it’s no skin off my nose".
It might also be used in the following scenario:
Or one might say "I’m going to tell the whole world what an arrogant insensitive person you are because you call yourself an "American" just because you live in the United States and you have no right to try to use that term exclusively because all of the people who live in the New World are Americans. So I really am going to tell the world what an arrogant jackass you are and how insensitive you are, and how arrogant you are".
I reply, "knock yourself out", meaning "Somehow this thing about the use of the word ‘American’ doesn’t bother me very much. I have a lot of other things I have to worry about that seem more important to me."
SR
