At starting school, still very young (5)
I believe the answer is:
seven
'very young' is the definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?
'at starting school still' is the wordplay.
'at' says to put letters next to each other.
'starting school' becomes 's' (I am not sure about the 'starting' bit.).
'still' becomes 'even' (synonyms).
's' next to 'even' is 'SEVEN'.
Can you help me to learn more?
(Other definitions for seven that I've seen before include "So many ages of man (AYLI)" , "Number of sins, seas or dwarves" , "VII" , "Theme of exotic dance" , "See 1" .)