How many meanings does the phrase Forget About It have?

Ex-FBI agent Joe Pistone infiltrated the Mafia, scoring a big win for the Federal agents and the FBI. Part of Pistone's cover was to learn the ins and outs of daily life with organized criminals. Talking the talk was a big part of it. His very life depended on how well he could blend in with the mottley crew.

The phrase "forget about it" was one of their catch-all's that had many meanings. Like the Eskimo's 240 Words for "snow". As far as anyone can tell, there are presently 56 definitions for this phrase.

Reference:The FBI Story by Don Whitehead, published Random House, NY 1956.