Blue skin
Blue skin was a term used by Aenar to describe Andorians.

In 2154, Jhamel described Shran as a blue skin and claimed to never have met one before. Shran wondered how the blind Aenar knew he had blue skin. She told him not to ask her to go into details, as she didn't have the scientific knowledge to explain. ()

See also
 Blue demon
 Pink skin
Slang
Andoria