ΔE 12.7, fair: the same colour family, but not a straight swap. Orc Green is more muted, cooler than Undergrowth Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Orc Green is more muted, cooler than Undergrowth Green.
The same difference applies the other way round: Undergrowth Green is 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 Undergrowth Green on the colour wheel See Orc Green on the colour wheel
All matches: Undergrowth Green equivalents · Orc Green equivalents