Maybe keener cabby managed to go round rarely empty (7)
I believe the answer is:
crybaby
'maybe keener' is the definition.
I can't tell whether this defines the answer.
'cabby managed to go round rarely empty' is the wordplay.
'managed' is an anagram indicator.
'to go round' indicates putting letters inside.
'empty' means to remove the middle letters.
'rarely' with its middle removed is 'ry'.
'cabby' is an anagram of 'cbaby'.
'cbaby' going around 'ry' is 'CRYBABY'.
Can you help me to learn more?
(Other definitions for crybaby that I've seen before include "One sheds tears easily" , "One shedding tears frequently" , "Person too easily reduced to tears" , "Immature weeper" , "(Very young?) weeper" .)