Everyone in this novel is above average height (7)
I believe the answer is:
tallish
'everyone in this novel is above average height' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
'everyone in this novel' is the wordplay.
'everyone' becomes 'all' (all people).
'in' means one lot of letters goes inside another.
'novel' indicates anagramming the letters (letters in a new or novel order).
'this' anagrammed gives 'tish'.
'all' inserted inside 'tish' is 'TALLISH'.
Can you help me to learn more?
(Other definitions for tallish that I've seen before include "rather large" , "Consider" , "Rather lofty" .)