obsequiousness, n. [sycophancy].
obsolete, a. [disused], archaic, [antiquated], unfashionable, [old-fashioned].
obstacle, n. [obstruction], [barrier], [impediment], [hindrance], [stumbling-block].
obstetrician, n. [midwife], [accoucheur].
obstetrics, n. tocology, [midwifery].
obstinacy, n. incompliance, doggedness, perversity, obduracy, intractability, stubbornness.
obstinate, a. incompliant, intractable, [mulish], [perverse], [dogged], contumacious, [stubborn]. Antonyms: [amenable], [yielding], tractable, [submissive], [compliant], [obedient].
obstreperous, a. [clamorous], vociferous, [noisy], [uproarious], [boisterous].
obstruct, v. [impede], [oppose], [retard], barricade, blockade, [clog], interrupt, [bar], [restrain].
obstruction, n. [obstacle], [impediment], [barrier], blockade, [restraint].