If Swash is grayed out, then you don’t have any Open Type fonts installed that include swashes such as Lovely Melissa, which comes with 1,372 glyphs and swashes for the reasonable price of $25 ...

Some fonts also include more typographic substitutions in the form of additional alternate glyph sets named contextual alternates, swash alternates, and titling alternates.

In most instances when people refer to fonts, ... Upright Italic (rare), Swash (usually an OpenType feature rather than a font). Optical sizes: Caption, Text, Subhead, Display, Deck, Poster.