Just one hand? (5)
I believe the answer is:
right
I believe this clue is a double definition.
'just' is the first definition.
(associated in meaning)
'one hand?' is the second definition.
(right is a kind of hand)
(Other definitions for right that I've seen before include "Just - correct - title" , "One has a claim to be correct" , "Conservative - correct" , "Correct; entitlement" , "The hand to the east when facing north" .)