On which infant advances a winning hand?
I believe the answer is:
allfours
'hand?' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see an association between them that I don't see?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for allfours that I've seen before include "We went down on them!" , "on which to crawl?" .)