Edward worried about learner, one falling behind (7)
I believe the answer is:
dawdler
'one falling behind' is the definition.
(to dawdle is to be slow or fall behind)
'edward worried about learner' is the wordplay.
'worried' is an anagram indicator.
'about' indicates putting letters inside.
'learner' becomes 'l'.
'edward' anagrammed gives 'dawder'.
'dawder' placed around 'l' is 'DAWDLER'.
(Other definitions for dawdler that I've seen before include "Slow coach" , "Loiterer" .)