Anybody's unit (3)
I believe the answer is:
one
I believe this is a double definition.
'anybody's' is the first definition.
(I've seen this in another clue)
'unit' is the second definition.
(synonyms)
(Other definitions for one that I've seen before include "Half of two" , "Hour after midnight" , "Single, unitary" , "joke" , "Individual" .)