That one-eyed couple, possibly in hand (5)
I believe the answer is:
jacks
'hand' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for jacks that I've seen before include "salts" , "Small bowls" .)