Abjure — To formally renounce or reject. He abjured his former political beliefs.

Abnegation — Self-denial; the rejection of a doctrine or belief. Her abnegation of material comforts impressed others.

Abstruse — Difficult to understand; obscure. The philosopher's abstruse arguments confused students.

Accolade — An award or privilege granted as a special honor. She received numerous accolades for her research.

Acerbic — Sharp and forthright; tasting sour or bitter. His acerbic wit often offended colleagues.

Aggrandize — To increase the power or reputation of someone, often in an exaggerated way. He sought to aggrandize himself through false claims.

Allay — To diminish or put at rest (fear or concern). The doctor tried to allay her patient's anxiety.

Amalgamate — To combine or unite to form one organization or structure. The two companies amalgamated into a single corporation.

Ambivalent — Having mixed feelings or contradictory ideas. She was ambivalent about accepting the job offer.

Anachronistic — Belonging to a period other than that being portrayed. The film was full of anachronistic dialogue.

Anodyne — Not likely to cause offense; painkillers (noun). His anodyne remarks failed to address the real issue.

Antediluvian — Of, or belonging to, the time before the biblical flood; old-fashioned. His antediluvian views on gender roles were outdated.

Apocryphal — Of doubtful authenticity, though widely circulated. The story of his heroics was likely apocryphal.

Apposite — Apt in the circumstances or in relation to something. Her apposite remarks summarized the debate perfectly.

Approbation — Approval or praise, especially from an authority. The plan received the committee's full approbation.

Arcane — Understood by few; mysterious or secret. The spell required arcane knowledge of ancient languages.

Ardor — Enthusiasm or passion. He pursued his art with great ardor.

Arrogate — To take or claim for oneself without justification. The general arrogated powers that belonged to civilians.

Ascetic — Characterized by severe self-discipline and abstention. The ascetic monk owned nothing but a robe.

Asperity — Harshness of tone or manner. She spoke with asperity about the repeated delays.

Assiduous — Showing great care, attention, and effort. The assiduous editor checked every fact twice.

Attenuate — To weaken or reduce in force or density. The signal was attenuated by the thick walls.

Aver — To state or assert confidently. The defendant averred his innocence throughout the trial.

Bolster — To support or strengthen. New evidence bolstered the prosecution's case.

Bombastic — High-sounding but with little real meaning; pompous. His bombastic speech impressed no one.

Bucolic — Relating to the pleasant aspects of the countryside. She painted bucolic scenes of rolling meadows.

Burgeon — To begin to grow or increase rapidly. The startup began to burgeon after its viral launch.

Capricious — Given to sudden and unaccountable changes of mood or behavior. The capricious weather ruined the outdoor wedding.

Castigation — Severe criticism or punishment. The employee faced castigation for the costly error.

Chicanery — The use of deception or subterfuge. The scandal involved financial chicanery at the highest levels.

Churlish — Rude in a mean-spirited way. It would be churlish to refuse such a generous offer.

Coda — The concluding passage of a piece of music or literature. The final chapter served as a coda to the trilogy.

Cogitate — To think deeply about something. She cogitated for hours before making her decision.

Compunction — A feeling of guilt or moral scruple. He showed no compunction about lying to the board.

Confound — To cause surprise or confusion; to prove wrong. Her recovery confounded the doctors.

Contentious — Causing or likely to cause argument; controversial. Immigration remained a contentious political issue.

Contrite — Feeling or expressing remorse for one's wrongdoing. The student was genuinely contrite about cheating.

Conundrum — A confusing or difficult problem. The ethical conundrum troubled the committee for weeks.

Corpulence — The state of being excessively overweight; obesity. His corpulence made physical activity difficult.

Credulous — Too willing to believe things; gullible. The credulous investor lost his savings to the scam.