dark-blue has definitions from the field of color
1
[ adjective ] (color) having a color similar to that of a clear unclouded sky

Examples

"October's bright blue weather"- Helen Hunt Jackson "a blue flame" "blue haze of tobacco smoke"

Used in print

(Morley Callaghan, A Passion in Rome....)

Changing his clothes , he put_on his dark-blue flannel suit , and laid away the gray jacket with the feeling that he might be putting it aside for_good .

Related terms

chromatic

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