hard-bitten vs hard-boiled

hard-bitten and hard-boiled both are adjectives.

Word	Noun	Adjective	Verb	Adverb
hard-bitten	No	Yes	No	No
hard-boiled	No	Yes	No	No

As adjectives, hard-bitten and hard-boiled are synonyms defined as:

Other synonyms of hard-bitten include pugnacious.

hard-bitten (adjective)	hard-boiled (adjective)
tough and callous by virtue of experience	(eggs) cooked until the yolk is solid
	used of persons; emotionally hardened
	tough and callous by virtue of experience