Figure auctioned around lunchtime (5)
I believe the answer is:
solid
'figure' is the definition.
(solid figure is a kind of figure)
'auctioned around lunchtime' is the wordplay.
'auctioned' becomes 'sold' (I've seen this in another clue).
'around' is an insertion indicator.
'lunchtime' becomes 'I' (one o'clock is I on a clock with Roman numerals).
'sold' going around 'i' is 'SOLID'.
(Other definitions for solid that I've seen before include "Firm; not liquid" , "Three-dimensional shape, not hollow" , "Shape with three dimensions" , "Strongly made or built" , "Firm - sound - reliable" .)