One word is best.
As much as I like the:
You look familiar. You got any warrants?
method, last night I defaulted to ‘No’ when I was approached last night by a female panhandler in the Publix parking lot. Because I keep my head up, I saw the encounter coming.
“Something, something, car, homeless.”
“Okay.” She then walked away.
I didn’t say it in an ugly way, just very firmly. The power of a firm ‘No’ is very strong.
I also had my pepper spray in hand in case things went any further.