Like yin and yang, for instance (13)

I believe the answer is:

complementary

(Other definitions for complementary that I've seen before include "Kind of 2 down treatment -- temple acronym (anag)" , "Interrelating, completing" , "Matching" , "Mutually enhancing" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.