ΔE 17.8, loose: different enough that you should pick on purpose. Forest Green is a little darker, more muted, cooler than Acid Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Forest Green is a little darker, more muted, cooler than Acid Green.
The same difference applies the other way round: Acid Green is a little lighter, 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 Acid Green on the colour wheel See Forest Green on the colour wheel
All matches: Acid Green equivalents · Forest Green equivalents