Order some frozen joints (6)
I believe the answer is:
Here is my best explanation:
'order' is the definition.
('enjoin' can be a synonym of 'order')
'some frozen joints' is the subsidiary indication.
'some' indicates the answer is hidden within the clue (Some of the parts of the word are used).
'enjoin' is hidden in the letters of 'frozen joints'.
(Other definitions for enjoin that I've seen before include "Command or forbid", "Advise", "Command (legal)", "Place an injunction on", "Order, urge", "Command, instruct", "Command to do something", "Impose an order upon", "Prohibit by order" and "Urge (to do something)".)