Pronunciation: [ʌnstˈampt] (IPA) 
The spelling of the word "unstamped" is easy to understand if you break it down phonetically. IPA transcription shows that "un" is pronounced as /ʌn/, "stamp" as /stæmp/ and "ed" as /ɛd/. Therefore, the correct phonetic spelling of "unstamped" is /ʌn stæmpt ɛd/. The word means that something has not been marked or approved with an official stamp. It is often used in legal documents or for items that require a stamp for validation.
Unstamped is an adjective that describes an object or material that lacks an official mark or impression, usually in the form of a stamp. The absence of such a stamp signifies that certain requirements or regulations have not been fulfilled, or that a particular authority has not approved or authenticated the item.
In the context of physical objects like documents, letters, or packages, being unstamped refers to the absence of a valid postage stamp or an official seal. This omission may indicate that the item has not been properly prepared for mailing or that it lacks the necessary authorization to be delivered through official channels. Without a stamp, the item may be deemed ineligible for transportation or processing by postal services.
The term can also be applied metaphorically to describe abstract concepts, such as ideas or actions. In this sense, when an idea or plan is deemed unstamped, it means that it lacks credibility, official validation, or endorsement. It suggests that the concept or proposal has not undergone critical evaluation or passed through the necessary channels to be considered legitimate or authoritative.
Overall, being unstamped implies the absence of an official mark or approval, either in physical or metaphorical terms.
Not stamped or impressed.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "unstamped" is formed by combining the prefix "un-" which means "not" or "lack of", and the word "stamped".
The etymology of "stamp" traces back to the Old French verb "estamper", meaning "to mark with a die or stencil" or "to emboss". It was derived from the Latin word "stuppare", which meant "to stop with a plug" or "to tampon".
Over time, the meaning of "stamp" broadened to include the action of impressing or making an official mark on something, typically using ink or a seal. For instance, official documents, letters, or parcels would be "stamped" with an official mark to indicate that proper or appropriate action had been taken.
The prefix "un-" is of Germanic origin and has been part of the English language since ancient times.
