Zodiac twins (6)
I believe the answer is:
gemini
'zodiac twins' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gemini that I've seen before include "Castor and Pollux constellation" , "Third sign of the Zodiac" , "Twins constellation" , "star group" , "Zodiacal twins" .)