The Oxford Thesaurus An A-Z Dictionary of Synonyms INTRO ...

happy-go-lucky, casual, relaxed, at ease; unenthusiastic,
apathetic; Colloq laid-back, together: How can you be so
nonchalant about important issues that affect all our lives?!
noncommittal
adj. wary, cautious, careful, gingerly, guarded, (playing it)
safe, circumspect, watchful, prudent, canny, tentative, on
guard, reserved, cool; precautionary or precautional,
precautious; Colloq playing it cool, playing it safe, playing it
or one's cards close to the chest: The company is still
noncommittal about the take-over of the American company.
non-completion
n. non-fulfilment, unfulfilment, non-performance,
incompleteness, deficiency: We regret the non-completion of the
work on your house and will refund in full the amount already
paid.
non-compliance
n. disobedience, nonconformity, non-observance, disregard,
disregarding, failure, non-cooperation, uncooperativeness,
unresponsiveness, rejection, refusal, denial: If you fail to
provide the records requested by the tax inspector, you can be
charged with non-compliance.
nonconformist
n. 1 nonconformer, renegade, maverick, rebel, radical,
individualist, heretic, dissenter, dissident, iconoclast, loner,
exception, anomaly: In the 1960s, Alastair counted himself
among the nonconformists who wore unconventional clothes and
flouted conventional behaviour.
--adj. 2 nonconforming, renegade, maverick, rebellious,
radical, individualist(ic), heretical, dissentient, dissident,
iconoclastic: Suffragists were ridiculed for their
nonconformist ideas.
nondescript
adj. indescribable, unclassifiable, unclassified, ordinary,
common-or-garden variety, common, commonplace, unremarkable,
colourless, drab, everyday, bland, uninteresting, insipid,
characterless, undistinctive, unexceptional: He was wearing
nondescript clothing and blended into the crowd.