Synonyms:

abstruse, darksome, dusky, involved,
ambiguous, deep, enigmatical, muddy,
cloudy, dense, hidden, mysterious,
complex, difficult, incomprehensible, profound,
complicated, dim, indistinct, turbid,
dark, doubtful, intricate, unintelligible.

That is _obscure_ which the eye or the mind can not clearly discern or
see through, whether because of its own want of transparency, its depth
or intricacy, or because of mere defect of light. That which is
_complicated_ is likely to be _obscure_, but that may be _obscure_ which
is not at all _complicated_ and scarcely _complex_, as a _muddy_ pool.
In that which is _abstruse_ (L. _abs_, from, and _trudo_, push) as if
removed from the usual course of thought or out of the way of
apprehension or discovery, the thought is remote, _hidden_; in that
which is _obscure_ there may be nothing to hide; it is hard to see to
the bottom of the _profound_, because of its depth, but the most shallow
turbidness is _obscure_. Compare COMPLEX; DARK; DIFFICULT; MYSTERIOUS.

Antonyms:

See synonyms for CLEAR.

* * * * *

OBSOLETE.

Synonyms:

ancient, archaic, obsolescent, out of date,
antiquated, disused, old, rare.

Some of the _oldest_ or most _ancient_ words are not _obsolete_, as
father, mother, etc. A word is _obsolete_ which has quite gone out of
reputable use; a word is _archaic_ which is falling out of reputable
use, or, on the other hand, having been _obsolete_, is taken up
tentatively by writers or speakers of influence, so that it may perhaps
regain its position as a living word; a word is _rare_ if there are few
present instances of its reputable use. Compare OLD.

Antonyms:

See synonyms for NEW.

* * * * *

OBSTINATE.

Synonyms:

contumacious, headstrong, mulish, resolute,
decided, heady, obdurate, resolved,
determined, immovable, opinionated, stubborn,
dogged, indomitable, persistent, unconquerable,
firm, inflexible, pertinacious, unflinching,
fixed, intractable, refractory, unyielding.

The _headstrong_ person is not to be stopped in his own course of
action, while the _obstinate_ and _stubborn_ is not to be driven to
another's way. The _headstrong_ act; the _obstinate_ and _stubborn_ may