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

people with respiratory disorders. 3 risky, dangerous, perilous,
life-threatening, touch-and-go: You might find it unhealthy to
criticize the government here.
unheard-of
adj. 1 unknown, unfamiliar, obscure, unidentified, nameless,
unsung: She is busy trying to promote some unheard-of sculptor.
2 unimaginable, undreamed of or undreamt of, unprecedented,
unimagined, unbelievable, inconceivable, unusual: They took the
unheard-of step of requiring that refunds be paid. Her starting
salary is an unheard-of œ100,000. 3 shocking, offensive,
outrageous, disgraceful, extreme, unthinkable, outlandish: The
victims were subjected to unheard-of tortures.
unheralded
adj. unannounced, unpublicized, unadvertised; unexpected,
surprise, unanticipated, unforeseen, unpredicted: Published by
some obscure company, the book turned out to be an unheralded
success.
unhesitating
adj. 1 swift, rapid, quick, immediate, instantaneous, prompt,
ready, unhesitant: The response was an unhesitating 'No!' 2
unfaltering, unwavering, wholehearted, unqualified, unswerving,
undeviating, staunch, steadfast, implicit, resolute: We
appreciate your unhesitating devotion to duty.
unhurried adj. leisurely, unrushed, easy, easygoing, casual, gradual,
deliberate, steady, sedate, calm: We proceeded at an unhurried
pace, eventually arriving at dusk at the castle gates.
unidentified
adj. nameless, anonymous, unknown, unmarked, unnamed, unknown,
unfamiliar, unrecognized, mysterious: The police found the body
of a unidentified woman in the park.
uniform adj. 1 homogeneous, consistent, unvaried, unchanged, unaltered;
unvarying, unchanging; invariable, unchangeable, unalterable,
regimented, standard; ordered, orderly, equal, even, like,
identical; alike: The mixture is uniform throughout. The rules
are uniform for everyone. Line up in ten uniform rows of ten
each. 2 even, unbroken, smooth, regular, flat: Not one
irregularity marred the uniform surface of the plain.