Appreciate model not having small figure (5)
I believe the answer is:
digit
'figure' is the definition.
(numerical figure)
'appreciate model not having small' is the wordplay.
'appreciate' becomes 'dig' (to dig can mean to appreciate or 'get').
'model' becomes 'sit' (e.g. for a painting).
'not having' suggests deleting specific letters.
'small' becomes 's' (abbreviation - e.g. clothes size).
'sit' with 's' removed is 'it'.
'dig'+'it'='DIGIT'
(Other definitions for digit that I've seen before include "finger, perhaps" , "a number less than ten" , "zero, one, two, three, four, five, six, seven, eight, or nine" , "Single number" , "E.g. toe" .)