Ask them to repeat themselvesGiphy
Hit them with a "what?" or an "excuse me?". Maybe they will realize how stupid they sound screaming about how pretty you are from their car or across the street. Maybe they'll just repeat themselves and then you can explain to them how stupid they sound.
Catcall Them BackGiphy
Give them a taste of their own medicine. Respond to their, "Hey beautiful!" with a "sup sexy". Will they be thrown off guard? Probably. Hopefully after that is said they will shut up.
Ask If They Talk To Their Mama Like ThatGiphy
Ask the guy if they talk to their mom, sister, or female friend like that. Ask them if they talk to them with some respect or if they are just an overall crappy person.
Tell Them They're WrongGiphy
Shut them down altogether and tell them it's straight up wrong to catcall. Tell them it's gross and offensive and let them know they aren't going to get anywhere by doing so.
Ask Them WhyGiphy
He yells hey beautiful or hey sexy or hey girl smile, just ask them why. Ask them why you're so pretty or why you need to smile. I bet you they will be stumped or just surprised that you're even asking why.