Leopard vs Lion
These two are in the same family, so the differences are in the detail.
Leopard
Panthera pardus
Lion
Panthera leo
Build is slender and muscular, with relatively short limbs and a notably broad head.
en.wikipedia.orgDark spots are grouped into rosettes, rings rather than solid marks, over pale yellow to dark golden fur.
en.wikipedia.orgAdult coat is plain tawny with no spots or rosettes; cub spots fade by adulthood.
en.wikipedia.orgMales carry a prominent mane covering the head, shoulders, and chest.
en.wikipedia.orgSmall whitish spots are visible on the back of each ear.
en.wikipedia.orgEars are distinctly rounded in shape.
en.wikipedia.orgTail is white-tipped and pale on the underside, with spots merging into bands near the tip.
en.wikipedia.orgTail tip carries a dark hairy tuft shared by all lions.
en.wikipedia.orgBoth are recorded in 5 of the same grid cells across Namibia, so a sighting in that overlap could be either.