noun , adjective
■ noun
[ sing. ] a situation that allows sth to happen, or that allows people to go to a place or get information without restrictions :
The government's policy is an open door to disaster.
An insecure computer system is an open door to criminals.
■ adjective ˌopen-ˈdoor [ only before noun ]
1.
( of a policy, system, principle, etc. ) allowing people or goods freedom to come into a country; allowing people to go to a place or get information without restrictions :
the country's open-door policy for refugees
2.
a policy within a company or other organization designed to allow people to freely communicate with the people in charge :
We operate an open-door policy here, and are always willing to listen to our students' suggestions.