ΔE 10.9, fair: the same colour family, but not a straight swap. Thar Brown is a little darker, more muted, warmer than Morghast Bone.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Thar Brown is a little darker, more muted, warmer than Morghast Bone.
The same difference applies the other way round: Morghast Bone is a little lighter, 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 Morghast Bone on the colour wheel See Thar Brown on the colour wheel
All matches: Morghast Bone equivalents · Thar Brown equivalents