ΔE 23.7, loose: different enough that you should pick on purpose. Foul Green is noticeably lighter, cooler than Bright Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 24). Foul Green is noticeably lighter, cooler than Bright Green.
The same difference applies the other way round: Bright Green is noticeably darker, 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 Bright Green on the colour wheel See Foul Green on the colour wheel
All matches: Bright Green equivalents · Foul Green equivalents