One run (6)
I believe the answer is:
single
I believe this is a double definition.
'one' is the first definition.
(synonyms)
'run' is the second definition.
(type of run in cricket)
(Other definitions for single that I've seen before include "Still miss" , "Individual - unmarried" , "Just one, or unmarried" , "Solitary or unwed" , "Free" .)