You have to ask the person using the term.

There are many past threads about this, but to recap anyway:

Víkingr

The term víkingr (masculine noun) in medival Old Norse (1200s-1400s Icelandic) refers to a "freebooter, sea-rover, pirate, viking" (Zoëga’s dictionary) "viking, pirate, raider, evildoer" (Fritzner's dictionary). There is also the feminine noun víking which refers to the journey itself. (Sá varð dauðr á vestrvegum í víkingu on the 11th century rune stone Vg 61. "He died on the western route in víking")

Out of thousands of rune stones of the Viking Age, only a few use the terms. Specifically three from Denmark, one from Gotland and the aforementioned one from Västergötland (Vg 61). The provinces of Uppland and Södermanland in Sweden, which alone account for over half of Viking Age rune stones, do not have a single one using the term. There is U 617 (AKA the Bro stone, erected near the church in Bro, across the road from the abandoned tent in the bushes that the municipality still hadn't removed last I checked despite my complaints) which memorializes a man who was a víkinga vǫrðr - "warder of vikings"; that is, someone who was in some form of guard force against them. (if the reading is correct; as this term is not known elsewhere we can't be entirely certain)

"Viking" was limited in use and always refers to specific people. People who wanted to brag used terms like _drengiligr _ - literally 'manly' and by extension, honorable, brave, loyal, etc. The term 'víkingr' was not a group identity. Certainly never as an ethnicity. Scandinavians consisted of Swedes, Danes, Norwegians, Geats and Gutes (Gotlanders) Futher subidivded into West- and East- Geats, Jutes and Bornholmers, Hordalendings and Trønder and so forth.

There's nothing indicating the Norse term was used for Scandinavian raiders only. On the contrary the most likely vikings in Uppland in the late 1000s that U617 refer to, would be Finnic peoples coming from the area around the Gulf of Finland.

The term may have been loaned into Old English wicing; but after the Viking Age it quickly fell out of use in English and in Scandinavian languages, except in Iceland where it persisted a bit longer in literature, as they composed new stories about the Viking Age long after it. (Fornaldarsögur)

19th century revival

The term only came back when Scandinavian historians began taking an interest in medieval Icelandic sagas in the 17th century. But it remained an obscure term for historians until the 19th century, when Romanticism in art lead to a huge surge in interest for Sagas and "vikings". In fact the present pop-cultural understanding of a "viking" was for all intents created then. Especially since interest in Viking Age and Scandinavian folklore also surged in Britain, a far more culturally influential nation. (here's a BBC article on that written by Professor Andrew Wawn, who's also written a full book) So it's at this point the term "viking" is introduced into English. Also, for that matter, the term "Norse" was also coined, in the sense of "medieval Scandinavian". Having been used as an adjective for all things Norwegian. (some argued at the time in favor of the term "Northmen" instead to avoid a Norwegian-specific connotation, but in the end it was "Norse" that lost its Norway-specificity instead)

Regarding the Viking Age

As I explained in a thread recently, modern historians of Scandinavia have generally accepted the term "Viking Age" for the period ~800-1060, as the last sub-period of the Nordic Iron Age. This since there are cultural changes that can be associated with its start and end. At the same time it's still recognized that the term is born out of nationalist and romanticist notions from the 19th century.

The notion of a Viking Age, and especially of a kind of homogenous Scandinavian "viking" culture, represnted by the three nations of Danes and Swedes and Norwegians, was borne out of romanticism and nationalism in the 19th century. There is disagreement on how problematic that is. Fredrik Svanberg wrote an influential PhD thesis (Decolonizing the Viking Age, 2004) in archaeology where he drew on postcolonial studies to liken this to a kind of colonization of the past, and maintained that even today's research is still dominated by nation-state thinking for instance. I would say most would agree with that but have different ideas on the extent of the problem. Most would not go so far (as he does) to consider the "Viking Age" (let alone 'viking') a term that ought to be abandoned. For instance, having an age in Scandinavia being defined by the beginning and ending of widespread raiding in England may be unsatisfactory from a Nordic perspective (hence one must look to other cultural changes), but it's completely reasonable from an British perspective. Which is a valid viewpoint too, after all.

Likewise, from a British perspective it does not necessarily make sense to distinguish Scandinavians by whether their activity was raiding, trading or invading; these things were not necessarily distinct and exclusive. Nor is it necessarily useful to distinguish them by their ethnic self-identities either; as parties often had a mixture of nationalities present. The locals at the time didn't bother to distinguish within the groups either.

So it remains fairly common for British historians to use 'vikings' as a term for Viking Age Scandinavians in Britain. Most historians of Scandinavia on the other hand don't use 'viking' as a general term for all Scandinavians of the Viking Age and discourage that use, sticking more closely to using it the way víkingr was. Most would not (for instance) object to talking about Finnic or Slavic "vikings", as we know raiders from those peoples existed around the Baltic in the Viking Age too. Norse peoples raided each other too. U 614 memorializes a man from Uppland who died taking a gjald (=exacting tribute) in Gotland. A viking by our standards, but they chose not to describe him as such.

The vast majority of people were peasants who did not raid at all, but even those who raided still ran farms. Even the kings of the Viking Age ran farms (or delegated it to their bryti). Royal wealth did not yet come from taxation but from the revenue generated by a set of crown-owned farms (the term Uppsala auðr is recorded in Old Norse as a collective term for the Swedish kings's estates, including ones not in Uppsala; individual estates are mentioned from Denmark and Norway) Virtually the entire population were subsistence farmers; the largest "urban" settlements only consisted of a few thousand people and were veritable villages even by contemporary European town-size metrics.