One man inside less gets resemblance (8)
I believe the answer is:
likeness
'resemblance' is the definition.
(I've seen this before)
'one man inside less' is the wordplay.
'one' becomes 'i' (Roman numeral).
'man' becomes 'ken' (short for Kenneth).
'inside' indicates putting letters inside.
'i'+'ken'='iken'
'iken' going into 'less' is 'LIKENESS'.
'gets' is the link.
(Other definitions for likeness that I've seen before include "Resemblance" , "Similitude" , "Picture" , "depiction" , "Good portrait" .)