In practice[inconsistent], the term is used within philately to refer to any stamp that appears to be unused with gum.
The term mint never hinged has developed to provide reassurance to buyers that the stamp has not been tampered with to remove traces of mounting, as the term unmounted mint was thought to be ambiguous.
Another common practice is to attempt to remove fiscal cancellations, which are often pen cancels, in order to change a stamp used fiscally (for tax purposes) to one apparently unused.
Stamps available for both postage and revenue (fiscal) purposes are usually worth more unused or with a postal cancellation.
Madame Joseph specialised in the addition of forged cancels to stamps that were worth more used than unused.