In the philosophy world, Modern Western Philosophy typically means circa 1500-1600-1700 or so and a class in the subject will include Hume, Locke, Descartes, etc.
In philosophy there's a well defined capital-M modernity, that breaks away from scholastic philosophy following the antique Aristotelian tradition, and attempts to re-invent philosophy starting in the late medieval period.
Modern philosophers are thus found from the renaissance up until the period that is referred by non-philosophers as modernity. This is because they themselves used the term modern.
Yes, I know what the word means in the standard sense. The point was that it doesn’t have a separate meaning in philosophy the way modern philosophy does.
Or in art, where modern art doesn’t mean “art of today” but instead “art of roughly 1880-1960.”