Sibyl, swapping outer layers for gown, starts to read some tea leaves (7)
I believe the answer is:
robbers
'leaves' is the definition.
Although both the answer and definition are plural nouns, I can't see how they can define each other.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for robbers that I've seen before include "Violent thieves" , "Thieves and burglars" , "Thieves who threaten violence" .)