Paris Hilton’s two-year-old learned a new word … and it’s a four-letter expletive he just won’t stop saying.

Paris just shared video of her son, Phoenix, dropping f-bombs left and right as he eats dinner in the kitchen … and she can’t help but laugh at her kid’s potty mouth.

Mom says she was recording her son eating food in hopes of capturing a sweet moment … but all she got was him repeatedly saying “f***” straight to her face.

Paris couldn’t help but laugh, and she says she probably shouldn’t be making light of his favorite new phrase but adds … “I can’t help it!! Toddlers are actually little comedians.”

In the video she asks Phoenix what he just said and he repeats it … then drops a couple more cute f-bombs as he smiles in his mom’s face.

Kids say the darndest things!!!