ΔE 21.4, loose: different enough that you should pick on purpose. Foul Green is noticeably lighter, more saturated than Cold Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Foul Green is noticeably lighter, more saturated than Cold Green.
The same difference applies the other way round: Cold Green is noticeably darker, more muted.
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 Cold Green on the colour wheel See Foul Green on the colour wheel
All matches: Cold Green equivalents · Foul Green equivalents