To me, “pulp” has many adjacent meanings, and in any situation where the term is used the meaning of it must (and usually can) be gleaned from the context, if it’s not explained outright.
In one context, it means adventure stories set during the interwar period and adjacent time periods. This has porous borders with some other genres including gangster fiction, Victorian penny dreadfuls and old-fashioned westerns.
In another but similar context, it includes Conan-style swords and sorcery (“pulp fantasy”), Flash Gordon-style retro sci-fi (“pulp sci-fi”), Cthulhu-style weird horror, and Zorro-style swashbuckling stories. The defining feature being that they all represent the culture of interwar-period pulp periodicals, novels, comics and films. Borders tend to be even more porous for this meaning, not least because these genres are also associated with other overlapping terms and concepts. For instance, Zorro is pulp but Captain Blood and Scaramouche are not quite, even though all are swashbuckling romances. Conan is pulp but Elric and Fafhrd & the Grey Mouser are not quite, even though all belong to the defining core of swords-and-sorcery fiction.
In a somewhat different context, pulp is anything with an “airport paperback” sort of vibe. So, Tom Clancy, Anne Rice and whoever the Britcrime mystery writer du jour is, are representative of pulp fiction in this context.
In short, use “pulp” as you will. People will get what you mean.