For a cousin on your father's side:
* 堂兄/堂弟 (táng xiōng/táng dì): Male cousin
* 堂姐/堂妹 (táng jiě/táng mèi): Female cousin
For a cousin on your mother's side:
* 表兄/表弟 (biǎo xiōng/biǎo dì): Male cousin
* 表姐/表妹 (biǎo jiě/biǎo mèi): Female cousin
General term for any cousin:
* 表兄弟姐妹 (biǎo xiōng dì jiě mèi): This is a more general term that can be used for any cousin, regardless of gender or their parent's relationship to you.
Example:
"My cousin is coming to visit me."
* 我的堂哥/堂姐/表哥/表姐要来我家看我。(Wǒ de táng gē/táng jiě/biǎo gē/biǎo jiě yào lái wǒ jiā kàn wǒ.)
Note: The specific term you use will depend on the context and who you are talking to.