Single people (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
ones
But I can't explain it at all! Could you help me understand?
(Other definitions for ones that I've seen before include "Aces" , "1 & 1 & 1" , "Singles" , "Individuals" , "(Of ship) returning to port of origin" .)