I. adjective
1.
not closed or obstructed
escaped through the open gate
Synonyms: patent, unclosed, unobstructed
Related Word: agape, dehiscent, gaping, patulous, ringent, wide, yawning; ajar; unbarred, unbolted, unfastened, unlocked, unsealed; clear, unimpeded
Contrasted words: blocked, obstructed; constricted, cramped, narrow, strait
Antonyms: closed, shut
2.
lacking a cover or covering
an open wound that continued to ooze blood
his chest open to the sun
Synonyms: bare, denuded, exposed, naked, peeled, stripped, uncovered
3.
Synonyms: liable 2, exposed, obnoxious, prone, sensitive, subject, susceptible
Antonyms: closed
4.
not restricted to a particular group or situation
favored open enrollment in the schools
Synonyms: accessible, open-door, public, unrestricted
Related Word: attainable, available, obtainable, reachable, securable
Idioms: to be had, within reach
Contrasted words: limited, restricted; inaccessible, private
Antonyms: closed
5.
available for use or consideration or decision
there are only two courses open to us
Synonyms: accessible, employable, operative, practicable, usable
Related Word: appropriate, fit, proper, suitable; acceptable, agreeable, pleasing
Idioms: within reach
Contrasted words: inaccessible, inoperative, unusable
Antonyms: closed
6.
Synonyms: doubtful 1, ambiguous, dubious, dubitable, equivocal, indecisive, problematic, uncertain, undecided, unsettled
7.
Synonyms: frank , candid, openhearted, plain, straightforward, unconcealed, undisguised, undissembled, undissembling, unvarnished
Antonyms: close; clandestine
II. verb
1.
to change from a closed to an open condition
open the window
Synonyms: ope, unblock, unclose, undo, unshut, unstop
Related Word: clear, free, release; bare, disclose, expose, reveal
Idioms: lay open, swing open, throw open
Contrasted words: block, occlude, stop
Antonyms: close, shut
2.
to make physically or mentally visible
dawn opened a surprising scene to his startled eyes
Synonyms: disclose, display, expose, reveal, unclothe, uncover, unveil
Related Word: adumbrate, hint, shadow, suggest
Idioms: bring to light, bring to ( or into) view, lay bare, make plain, show forth
Contrasted words: cloak, conceal, hide, screen, secrete, shroud
3.
to make an opening in
decided to open a can of beans
Synonyms: breach, disrupt, hole, rupture
Related Word: break, broach, tap, undo; cut, gash, slash; perforate, pierce
Idioms: lay open
Contrasted words: occlude, shut; fasten, secure
Antonyms: close
4.
to spread out
the eagle slowly opened its mighty wings
Synonyms: expand, extend, fan (out), outspread, outstretch, spread, unfold
Related Word: billow, dilate, distend, swell; cover, mantle, overspread
Contrasted words: collect, concentrate, contract, gather (in)
Antonyms: close
5.
Synonyms: begin 1, commence, embark (on or upon), get off, inaugurate, initiate, jump (off), kick off, launch, start
Antonyms: close
6.
Synonyms: convene 1, meet, sit
III. noun
Synonyms: outdoors , open air, out-of-doors, outside, without