The most nearly opposite word to "liege" would be "servant" as a liege is someone who owes loyalty to a superior, whereas a servant is someone who serves others.
Cowardice is nearly the opposite in meaning of valor.
A synonym of course. An antonym for a word that is defined for hvaing the opposite or nearly the opposite meaning.
savant.
"Asserts" or "claims" are phrases that are mostly nearly the same in meaning as "avouches."
Could be.... But the knock-kneed knight nearly knew to knock on knickers nightly... ... is more so.
Servant
Cowardice is nearly the opposite in meaning of valor.
A synonym of course. An antonym for a word that is defined for hvaing the opposite or nearly the opposite meaning.
of Delay
Leniency
Defeated
dawdle
savant.
immoral, unethical
unethical.
Smooth
Words that are opposite or nearly opposite in meaning are called antonyms.Examples are big and small, or long and short. Not all words have antonyms.When two antonyms are used together for effect, it is called an oxymoron.(see the related question)