"I'm 15."

Just eat a lemon. Look them in the eyes and eat a freakin' lemon.

Proven by my friend Alex to ward off the unwanted.

Shout "stranger danger!" at the top of your lungs.

"I'm deaf."

Shout it at him so he really gets the idea.

"No hablo Ingles."

"I don't ethically support men asking women for their numbers. Or dating. Or men."

"What's your zodiac sign? I need to make sure we're compatible first."

"I have HPV."

Or any other STD will do.

"The judge says I can't have my phone until the charges are dropped against me for reckless endangerment of others."

 "Oh my god, YES! I need a new gay best friend! You're gay, right?"

 "I'm just getting some real small dick energy from you, I'm sorry."

 "I'm saving myself for Chris Evans."

 "Mercury is in retrograde and I just can't make any big decisions right now."

 "Sorry, my mom said I can't."

 "I'm wearing a chastity belt that only my parents and God have the key to."

 "I'm on the run from the police for suspected murder of my ex."

 "My horoscope advised me against doing anything reckless."

 "I'm actually in an arranged marriage with my cousin. We like to keep it in the family."

Kill that mood, real quick.

 "I'm in love with you."

 Laugh uncontrollably until they walk away.

 Or cry uncontrollably. Dealer's choice.

 "You'll have to ask my dad's permission first."

 "Sorry, my cat just died, so I'm too fragile."

 "Yeah, I would, but I have to go shampoo my dog. Like, right now."

 "Yeah, can you text me around 3 o'clock and remind me to take my meds? My schizophrenia really acts up if I don't remember to take them."

 Hiss at him, like a cat.

 "It's not me, it's you."

Nothing like a premature breakup to reject him.

 "No, I can give you my boyfriend/girlfriend's number instead, though."

 "Oh, I think someone's calling me from the other side of the bar, byeeeee."

 "Gosh darnit, I JUST joined a convent and had to give up my worldly possessions today, sorry."

 "Sorry, I'm still traumatized from my parents' messy divorce when I was 10."

 "No."

This goes against what the headline says, but I'm a firm believer that a simple "no" is effective and will send the guy packing.