In a group, one girl has a can-opener (5)
I believe the answer is:
class
'in a group one' is the definition.
I can't tell whether this defines the answer.
'girl has a can-opener' is the wordplay.
'girl' becomes 'lass' (lass can informally mean a girl).
'has' means one lot of letters go next to another.
'opener' suggests taking the first letters.
The initial letter of 'can' is 'c'.
'lass' after 'c' is 'CLASS'.
Can you help me to learn more?
(Other definitions for class that I've seen before include "Form; stylishness" , "Teaching group" , "School group" , "Where one learns" , "Genus" .)