ΔE 21.6, loose: different enough that you should pick on purpose. Fluorescent Violet is noticeably darker, much more muted, cooler than Fluorescent Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Fluorescent Violet is noticeably darker, much more muted, cooler than Fluorescent Purple.
The same difference applies the other way round: Fluorescent Purple is noticeably lighter, much more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Fluorescent Purple on the colour wheel See Fluorescent Violet on the colour wheel
All matches: Fluorescent Purple equivalents · Fluorescent Violet equivalents