Turns out to be the smallest of the litters (5)
I believe the answer is:
runts
'be the smallest of the litters' is the definition.
I can't judge whether this definition defines the answer.
'turns out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'turns' with letters rearranged gives 'RUNTS'.
'to' is the link.
Can you help me to learn more?
(Other definitions for runts that I've seen before include "Smallest of litters" , "Small pigs" , "Smallest animals in a litter" , "Littlest pigs" , "Small piglets" .)