Obdurate = ob⋅du⋅rate  [ob-doo-rit]
–adjective
1. unmoved by persuasion, pity, or tender feelings; stubborn; unyielding.
2. stubbornly resistant to moral influence; persistently impenitent: an obdurate sinner.
Obdurate

Ob"du*rate\, a. [L. obduratus, p. p. of obdurare to harden; ob (see Ob-)+ durare to harden, durus hard. See Dure.]1. Hardened in feelings, esp. against moral or mollifying influences; unyielding; hard-hearted; stubbornly wicked. The very custom of evil makes the heart obdurate against whatsoever instructions to the contrary. --Hooker. Art thou obdurate, flinty, hard as steel, Nay, more than flint, for stone at rain relenteth? --Shak. 2. Hard; harsh; rugged; rough; intractable. "Obdurate consonants." --Swift. Note: Sometimes accented on the second syllable, especially by the older poets. There is no flesh in man's obdurate heart. --Cowper. Syn: Hard; firm; unbending; inflexible; unyielding; stubborn; obstinate; impenitent; callous; unfeeling; insensible; unsusceptible. Usage: Obdurate, Callous, Hardened. Callous denotes a deadening of the sensibilities; as. a callous conscience. Hardened implies a general and settled disregard for the claims of interest, duty, and sympathy; as, hardened in vice. Obdurate implies an active resistance of the heart and will aganst the pleadings of compassion and humanity. -- Ob"du*rate*ly, adv. -- Ob"du*rate*ness, n.

Avidity = a⋅vid⋅i⋅ty [uh-vid-i-tee]
–noun
1. eagerness; greediness.
2. enthusiasm or dedication.
Avidity

A*vid"i*ty\, n. [L. aviditas, fr. avidus: cf. F. avidit['e]. See Avid.] Greediness; strong appetite; eagerness; intenseness of desire; as, to eat with avidity. His books were received and read with avidity. --Milward.