The document defines the word "obdurate" as meaning pigheaded or stubborn. It then lists synonyms for obdurate such as adamant, bullheaded, callous, dogged, firm, fixed, hard, harsh, heartless, immovable, implacable, inflexible, inexorable, mean, obstinate, perverse, relentless, rigid, tough, unbending, uncompromising, uncooperative, unemotional, unfeeling, unrelenting, and unyielding. The document also provides antonyms for obdurate like amenable, gentle, submissive, susceptible, and yielding.