Tabby is trained to look after the young ones (7)
I believe the answer is:
babysit
'look after the young ones' is the definition.
I can't tell whether this definition defines the answer.
'tabby is trained' is the wordplay.
'trained' indicates anagramming the letters (to train can mean to grow something into a shape).
'tabby'+'is'='tabbyis'
'tabbyis' is an anagram of 'BABYSIT'.
'to' is the link.
Can you help me to learn more?
(Other definitions for babysit that I've seen before include "Mind" , "Look after children temporarily" , "Supervise in loco parentis" , "Tend to kid" , "Take charge to allow parents to go out" .)