ΔE 15.3, loose: different enough that you should pick on purpose. Ferocious Green is noticeably lighter, more muted, warmer than Greenskin Punch.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Ferocious Green is noticeably lighter, more muted, warmer than Greenskin Punch.
The same difference applies the other way round: Greenskin Punch is noticeably darker, more saturated, 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 Greenskin Punch on the colour wheel See Ferocious Green on the colour wheel
All matches: Greenskin Punch equivalents · Ferocious Green equivalents