Origin: 1300–50; ME
chevalrous < MF
chevalerous, equiv. to
chevalier chevalier +
-ous -ous 
Related forms: chiv⋅al⋅rous⋅ly, adverb
chiv⋅al⋅rous⋅ness, noun
Synonyms:
1. fearless, dauntless, valiant; courtly; faithful, true, devoted.
Antonyms:
1. cowardly, rude, disloyal.