I once dated a "Heimishe" girl who described heimish to me as "the best of both worlds"
I thinks she meant, the best of the Litvaks/Yeshivish and the best of the Chasiddim
I wanted to ask her, "so you mean a Heimishe person learns like the yeshivishe and davens, and follows Rebbes, like the Chasiddim.
I think she meant someone in the middle, "chilled out"
I'm not really sure what that means, but, to me Heimish has no clear meaning, usually we describe it as someone who's in the middle
e.g.: My Uncle describes himself as Heimish; clean shaven, perfect heimishe yiddish, down hat, goes to some Rebbes, eats heimish, has a somewhat Chasiddish Rov, in other words, leans toward Chasiddish without the garb.
Yet he can't stand Litvaks or Lutvaks as he calls them, and doesn't much like like hardcore Chasiddim.
So, what is Heimish
Note: people would describe me as Heimish, yet since Heimish has no Spiritual basis I reject that