ΔE 48.8, loose: different enough that you should pick on purpose. Khaki Drill is noticeably darker, much more muted, warmer than Zealot Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 49). Khaki Drill is noticeably darker, much more muted, warmer than Zealot Yellow.
The same difference applies the other way round: Zealot Yellow is noticeably lighter, much 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 Zealot Yellow on the colour wheel See Khaki Drill on the colour wheel
All matches: Zealot Yellow equivalents · Khaki Drill equivalents