ΔE 26.8, loose: different enough that you should pick on purpose. Goblin Green is noticeably lighter, much more saturated, warmer than Orc Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 27). Goblin Green is noticeably lighter, much more saturated, warmer than Orc Green.
The same difference applies the other way round: Orc Green is noticeably darker, much more muted, cooler.
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 Orc Green on the colour wheel See Goblin Green on the colour wheel
All matches: Orc Green equivalents · Goblin Green equivalents