Synonyms for Open:

adj.

accessible; not forbidden (adjective)
employable, permitted, attainable, operative, allowable, practicable, unrestricted, public, usable, unoccupied, admissible, vacant, welcoming.
artless (adjective)
undeceitful, callow, overt, Plain-spoken, natural, downright, unrestrained, ingenuous, trusting, un-artificial, blunt, artless, straightforward, undisguised, unsophisticated, undeceptive, broad, unaffected, naive, Unartful, uncalculating, direct, Unbeguiling, outgoing, sincere, honest, candid, undeceiving, frank, genuine, plain.
clear, obvious (adjective)
plain, conspicuous, frank, well-known, apparent, overt, undisguised, downright, manifest.
defenseless (adjective)
unguarded.
direct (adjective)
person-to-person.
free (adjective)
unrestricted.
honest, objective (adjective)
straightforward, transparent, candid, natural, ingenuous, unreserved, sincere, artless.
informative (adjective)
communicative.
open (adjective)
agape, out, unlocked, Admitting, patent, unobstructed, manifest, unbarred, unimpeded, yawning, uncovered, Unclosed, uncapped, unstopped, unplugged, unbolted, ajar, bare, gaping, exposed, accessible.
opened (adjective)
unlocked.
plainspoken (adjective)
Plain-spoken, man-to-man.
simple (adjective)
artless.
susceptible (adjective)
liable, apt, responsible, vulnerable, susceptible, prone, likely.
talkative (adjective)
expansive.
unfastened, unclosed (adjective)
exposed, expansive, airy, susceptible, yawning, removed, unplugged, wide, extensive, rent, unbarred, unbolted, unimpeded, agape, bare, uncovered, unobstructed, gaping, spacious, ajar, unlocked, accessible, patent, unstopped, unblocked.
unprotected (adjective)
unprotected.
veracious (adjective)
undeceptive.

adv

amazed (adverb)
agape.

n.

unwritten, known, taken, in the public domain, barred, unclassified, unblocked, removed, transparent. brokerage, cannibalize, conspicuous, business, safe, apart, book, insecure, secluded, unsafe, asset, capacity, Broking, business plan, account, beauty parade, unguarded. uncertain, controversial, enterprising, have/keep an open mind, adaptable, tolerant, live and let live, debatable, questionable. solid, get out, find your tongue, throw in, firm, add, continue, begin, bring up, airy, break your silence, penetrable. blink, adjust, screw up, squeeze, see, pop, focus. sensible, rational, Grounded, unprotected, protection, balanced, pragmatic, mature, practical, logical, Clear-headed, realistic. cross-selling, aftermarket, cold call, credit rating, customer care, buyer's market, direct marketing, call, churn rate, open door, detail. Susceptive, doable, in principle, be able to do something, attainable, viable, humanly possible, feasible, may. amenable, extemporize, open-minded, entertain, emcee, conjure, go on, accept, DO, debut, responsive, amuse, appear, acceptant. hyperactive, site, employable, anterior, practicable, possible, operable, pectoral, function, posterior, cervical, usable, region, utilizable, operative, prehensile. uninhabited, owned, fall/fit into place, unoccupied, originate, arise, develop, come into being, commence, arrive, unreserved, set in. crook, bestride, burrow, double over, balance, crane, crouch, bow, cower. borrow, bank, draw, pay in, mortgage, debit, credit. come up, bloom, choke, fade, bear, come out, die back, bud, climb. cash-and-carry, commercially, cut rate, brand name, custom, commercial, custom-built, custom-made, branded, consumable. interactive, one-on-one, illocutionary, communicative, verbal, nonverbal, one-to-one, paralinguistic, expressive, person-to-person. pry, force, burst open, unscrew, crack something open, try. obvious (noun)
apparent, well-known, obvious.

v.

begin (verb)
bow, start, commence.
clear, expose; spread (verb)
undo, unlock, pop, reveal, release, unseal, uncork, disclose.
closed (verb)
tight.
open (verb)
unlock, expose, reveal, unseal, disclose, undo, unplug, release, uncork.

Other synonyms:

get out, debit, pucker, unsure, responsive, practicable, operative. amenable, pop, adjust, start up, indefinite. function, hawk, add, straight, go into. dribble. bend, uncertain, kick. bank, draw, credit. set up, wave. drop. extend
crane.
permeable
penetrable.
reveal
expose.
unprotected
unprotected.
unreserved
expansive.

Usage examples for open

  1. " Then the way is open to come to Him. – Elsie at Nantucket by Martha Finley
  2. If only there was some one in the world to whom she could open her heart! – Bertha Garlan by Arthur Schnitzler
  3. The Eatons kept open house. – Roosevelt in the Bad Lands by Hermann Hagedorn