Sun for example upped class (5)
I believe the answer is:
genus
'class' is the definition.
(I've seen this in another clue)
'sun for example upped' is the wordplay.
'for example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'upped' shows that the letters should be reversed in order (in down clue, made to go up).
'sun'+'eg'='suneg'
'suneg' in reverse letter order is 'GENUS'.
(Other definitions for genus that I've seen before include "Part of the family" , "Taxonomic category above species" , "Group of plants with common characteristics" , "group of organisms" , "Latin class?" .)