obscuridad, f., darkness, obscurity.
obscuro, dark.
obsequiar, to serve, favor, treat kindly.
obsequio, obsequiousness, civility, treat; hacer un —, to show (a) courtesy, do a favor.
observación, f., observation.
observar, to observe, notice, see.
observatorio, observatory.
obstáculo, obstacle.
obstante; no —, nevertheless.
obstinación, f., persistency, obduracy.