What is Hi-by?
1.
When you meet a friend in the street and you're both in a hurry to go places...
A quick hello or alrite as you pass each other... or frantic conversation..
All right, how are you?
Not bad, not bad!
Must go see you around i'm sure!
-end of conversation
now thats a hi-by
See
2.
when someone walks by you and says hi, without stopping to chat
Moesha did her usual morning hi-by to me, while I was chillin' in my cubicle!