The reverse of the coin shows the crowned shield bearing the Royal Arms of the United Kingdom within the Garter of the Order of the Garter, with the motto HONI · SOIT · QUI · MAL · Y · PENSE · inscribed on it.
"Honi soit qui mal y pense" is an Anglo-Norman maxim which means "Shame on whosoever would think badly of it," or "May he be shamed who thinks badly of it". Its literal translation from Old French is "Shame be to him who thinks evil of it."
The shield is quartered, depicting in the first and fourth quarters the three passant guardant lions of England; in the second, the rampant lion and double tressure flory-counterflory of Scotland; and in the third, a harp for Ireland. At centre, an escutcheon of the arms of the Kingdom of Hanover, of which King George IV was King as Georg IV. Augustus Friedrich; the shield is crowned with the Crown of Charlemagne - reflecting the King's role as Arch-Treasurer of the Holy Roman Empire.
The crown on top is St Edward's Crown, named after Saint Edward the Confessor, one of the last Anglo-Saxon kings of England. It has been traditionally used to crown English and British monarchs at their coronations since the 13th century, with a two-century gap between 1689 and 1911 so King George IV was not himself crowned with it.
Around below, the date of issue ANNO [year] (from Latin: Year [year]).