ΔE 25.3, loose: different enough that you should pick on purpose. Bright Yellow Green is noticeably lighter, more saturated, warmer than Mortarion Green Clear.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Bright Yellow Green is noticeably lighter, more saturated, warmer than Mortarion Green Clear.
The same difference applies the other way round: Mortarion Green Clear is noticeably darker, 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 Mortarion Green Clear on the colour wheel See Bright Yellow Green on the colour wheel
All matches: Mortarion Green Clear equivalents · Bright Yellow Green equivalents