你个头

nǐ ge tóu

(coll.) my ass!; yeah, right! (used to mock a claim sb just made, as in 專家你個頭|专家你个头[zhuan1 jia1 ni3 ge5 tou2] "expert", my ass!)

你

nǐ

you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)

个

ge

used in 自個兒|自个儿[zi4 ge3 r5]

头

tóu

head