They think one is the carer (5)
I believe the answer is:
minds
'they' is the definition.
Both the definition and answer are plural nouns.
Maybe they are linked in a way I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for minds that I've seen before include "Tends; objects to" , "Looks after for a while" , "Objects to; brains" , "Objects to; intellects" , "Takes care of" .)