Uncovered Call

A short call option position in which the writer does not own the corresponding number of shares of the underlie or has not deposited in a cash account an amount equal to the exercise value of the call.

Unwind Event

It means to rectify or close a transaction in which a mistake has been made. For example, because of a misunderstanding, a brokerage firm may have bought the wrong stock for a customer. The firm must then unwind the erroneous trade by selling the stock just purchased and buying the correct stock.