A speculative option which the buyer or grantor does not have the resource in metal to cover. 
An opportunity to buy stock at a fixed price, offered by a seller who does not own the stock to back up the promise. If the buyer wants to exercise the option, the seller must purchase the stock at market price to make good on the offer.
Is an open option position which is not covered or hedged. Frequently, it is used in the context of a sold option position. 
[n] - a put or call option for which the seller or buyer has no underlying security position
noun a put or call option for which the seller or buyer has no underlying security position