Martial means to do with war and the military. Martial law, martial arts, a martial bearing.
Martial law is the army taking over the functions of civil government, and it is a grave step rather than a figure of speech. Watch the spelling against marital, which means to do with marriage — the two are one letter apart and the mistake is famous.
1adjectivemartialTo do with war and the military.
“The soldiers marched past to loud martial music.”
martial is a quality of war.
Latin martialis means of Mars, the Roman god of war. The month of March is named after the same god.
Latin
mārtiālis — of or pertaining to Mars, the Roman god of war
Middle French
martial
Middle English
martial
English, today
martial
Built from
From Middle English martial, marcial, mercial, mercialle (“relating to war, warlike; military; for use in fighting or warfare; brave, hardy; combative, fierce; ruthless, vicious; domineering, overbearing”), from Middle French martial (modern French martial (“martial”)), or directly from its etymon Latin mārtiālis (“of or pertaining to Mars, the Roman god of war”), from Mārtius (“of or pertaining to Mars”) + -ālis. The English word is cognate with Italian marziale (“martial”), Portuguese marcial (“martial”), Spanish marcial (“martial”).
Etymology from Wiktionary, CC BY-SA