"open" en el diccionario Collins English Cobuild & Thesaurus

open
adj

1 agape, ajar, expanded, extended, gaping, revealed, spread out, unbarred, unclosed, uncovered, unfastened, unfolded, unfurled, unlocked, unobstructed, unsealed, yawning

2 airy, bare, clear, exposed, extensive, free, navigable, not built-up, passable, rolling, spacious, sweeping, uncluttered, uncrowded, unenclosed, unfenced, unsheltered, wide, wide-open

3 accessible, available, free, free to all, general, nondiscriminatory, public, unconditional, unengaged, unoccupied, unqualified, unrestricted, up for grabs (informal) vacant

4 apparent, avowed, barefaced, blatant, bold, clear, conspicuous, downright, evident, flagrant, frank, manifest, noticeable, obvious, overt, plain, unconcealed, undisguised, visible

5 arguable, debatable, moot, undecided, unresolved, unsettled, up in the air, yet to be decided

6 disinterested, free, impartial, objective, receptive, unbiased, uncommitted, unprejudiced

7 (with) to an easy target for, at the mercy of, defenceless against, disposed, exposed, liable, susceptible, vulnerable

8 above board, artless, candid, fair, frank, guileless, honest, ingenuous, innocent, natural, sincere, transparent, unreserved

9 filigree, fretted, holey, honeycombed, lacy, loose, openwork, porous, spongy

10 bounteous, bountiful, generous, liberal, munificent, prodigal

11 exposed, undefended, unfortified, unprotected
vb

12 begin, begin business, commence, get or start the ball rolling, inaugurate, initiate, kick off (informal) launch, put up one's plate, set in motion, set up shop, start

13 clear, crack, throw wide, unbar, unblock, unclose, uncork, uncover, undo, unfasten, unlock, unseal, untie, unwrap

14 expand, spread (out), unfold, unfurl, unroll

15 come apart, crack, rupture, separate, split

16 disclose, divulge, exhibit, explain, lay bare, pour out, show, uncover

Antonyms
, adj

1 & 2 bounded, closed, concealed, confined, covered, crowded, enclosed, fastened, limited, locked, obstructed, restricted, sealed, shut

3 & 4 covert, disguised, hidden, inaccessible, private, protected, restricted, secret, veiled

6 biased, partial, prejudiced

7 & 11 defended, protected

8 artful, cunning, introverted, reserved, secretive, sly, withdrawn
vb

12 close, conclude, end, finish, terminate

13 block, close, fasten, lock, obstruct, seal, shut

14 fold