"Hello" is the answer as it make sense.
"Hlw" is an abbreviation of "heylow" which is a slang word of "hello".
What does hlw mean in texting?
Are you definitely sure it is a common slang term? I looked it up in the Urban Slang Dictionary (a source of all the most relevant text slang among other things), and it is showing up as undefined:
- High level waste
- How Language Works
- High Low Water
- Hybrid Large White (a type of turkey apparently)
Maybe if you could let me know a bit more about who said this to you and what the context of he conversation was, I may be able to deduce a meaning and give you a more accurate answer!