People in competition (4)
I believe the answer is:
race
I believe this clue is a double definition.
'people' is the first definition.
(people can mean a national group or race)
'competition' is the second definition.
(I know that race is a type of race)
'in' is the link.
(Other definitions for race that I've seen before include "Run quickly" , "Run - competition" , "Care about contest" , "Breed" , "Run, dash" .)