Okay, OK, Oh Kay, Oki, Oky, Kay, Mk, or simply K is a colloquial English word denoting approval, assent, or acknowledgment that has been a loanword from English for many other languages. As an adjective it means "adequate," "acceptable" ("this is okay to send out"), often in contrast to "good" ("the food was okay"); it also functions as an adverb in this sense. "Okay" can also be used to defuse a situation or to calm someone ("It's okay, it's not that bad"). As an interjection, it can denote compliance ("Okay, I will do that"), or agreement ("Okay, that's good"). As a grammatical particle it does not modify any other particular word, but rather reinforces the general point being made, particularly if that point is being called into question. And so, for example, a response to “So the accident kept him from going to the reunion?” might be “Oh, he went to it okay, but he had bruised ribs and his car was a wreck.” In this case “okay” does not modify him or his going anywhere; it is a particle emphasizing the point that is being questioned. As a noun and verb it means "assent"; ("The boss okayed the purchase"). The origins of "okay" are not known with certainty, and have been the subject of much discussion over the years

A tip (also called a gratuity) is a voluntary extra payment made to certain service sector workers in addition to the advertised price of the transaction. Such payments and their size are a matter of social custom. Tipping varies among cultures and by service industry. Though by definition a tip is never legally required, and its amount is at the discretion of the patron being served, in some circumstances failing to give an adequate tip when one is expected may be considered very miserly, a violation of etiquette, or unethical.

So they're not acronyms.

Actually, they are. I'll give up one, just for your trouble:

O.K. is short for "of knowledge," is what my teacher explained. As in, "'Let's go see a movie today.' 'I'm of knowledge of our plans.'"

I'm not sure how we warped the meaning so much to mean positive/negative and such.

Tenuous Insignificant Person?

Nice try, but no.

How about To Insure Promptness.

That's really what it is. Look it up.