Dandiprat (noun) (archaic)
A young or insignificant person.
Early 16th century (denoting a coin worth three halfpence)
“He’s a self obsessed dandiprat!”
Pompous or extravagant in language, style, or manner, especially in a way that is intended to impress.
Late 16th century: from Latin grandiloquus, literally ‘grand-speaking’, from grandis ‘grand’ + loqui ‘speak’. The ending was altered in English by association with eloquent.