I am 420 friendly

This is an idiom I have not seen before.
I am currently looking at some ads for housing and this appears quite often. Would anyone pls. explain what it means? Thank you.
  • A90Six

    Senior Member
    England - English.
    Paulfromitaly said:
    How would you actually pronounce it?

    four two o friendly? four hundred and twenty friendly?
    maybe either in another way?
    It's an AE thing and it would be pronounced, four-twenty, as it signifies the date, April 20th. This is a date unofficially recognised as "National Smokers' Day".