Usage 1: Shelley wrote in 'Revolt of Islam' (iv.9) "Custom maketh blind and obdurate The loftiest hearts." The adverb is "obdurately" and the noun, "obduracy." They all come from the transitive and intransitive verb obdure "to harden."

Suggested usage: The neutral sense can be used where you might otherwise use "dyed-in-the-wool," e.g. "His father was a union leader and he has been an obdurate Labourite since childhood." Of course, Tories might think this the pejorative usage. Here is a clearer example of that first meaning, "I. D. Nye was born to politics; his father was an obdurate card sharp until his death."

Etymology: From Late Latin obduratus, past participle of obdurare "to harden," derived from Latin durus "hard," also found in "endure" and "durable." "Durus" comes from PIE *deru-/*doru- "solid, tree" which emerged as daru "wood" in Sanskrit, Modern Hindi "dArU," Persian "dâr." Elsewhere the stem underwent liquid metathesis (the [r] and the vowel switched places) so that in Serbian it emerges as drevo "wood" (Russian derevo), and in English it evolved into both "tree" and "true" ("treow" and "treowe," respectively, in Old English). In Greek it turned up as drus "oak" and dendron "tree." By the way, "druid" is probably a borrowing from a Celtic compound *dru-wid- "strong seer," where "wid" is akin to "video" and "vision." (Our FAQ sheet has more about PIE. We would have to be perversely obdurate not to recognize Patricia Collins' contribution in suggesting today's word.)