ΔE 11.3, fair: the same colour family, but not a straight swap. Medium Grey Blue is a little lighter, cooler than Viridian Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Medium Grey Blue is a little lighter, cooler than Viridian Green.
The same difference applies the other way round: Viridian Green is a little darker, 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 Viridian Green on the colour wheel See Medium Grey Blue on the colour wheel
All matches: Viridian Green equivalents · Medium Grey Blue equivalents