1. Affording free passage or access
2. Affording unobstructed entrance and exit; not shut or closed; SYN. unfastened.
3. Not having been filled
4. Not sealed or having been unsealed; SYN. opened.
5. Not brought to a conclusion; subject to further thought; SYN. undecided, undetermined, unresolved.
6. Displayed before or in view of all
8. Not secret
9. Ready for business
10. Receptive to new ideas
11. Relatively empty of and unobstructed by fences or hedges or headlands or shoals
12. Sincere and free of reserve in expression
13. Used of mouth or eyes; SYN. opened.
14. Without undue constriction as from e.g. tenseness or inhibition
15. Accessible to all
16. Having no protecting cover or enclosure
17. Lax in enforcing laws; SYN. wide-open, lawless.
18. Not requiring union membership
19. (Mathematics) Of a set; containing points whose neighborhood consists of other points of the same set, or being the complement of an open set; of an interval; containing neither of its end points.
ETYM as. open; akin to Dutch open, os. opan, German offan, Icel. opinn, Swed. öppen, Dan. aaben, and perh. to Eng. up. Related to Up, and Ope.