Rising star, for example, showing class (5)
I believe the answer is:
genus
'class' is the definition.
(I've seen this in another clue)
'rising star for example' is the wordplay.
'rising' is a reversal indicator (letters written upwards in a down clue).
'star' becomes 'sun' (the Sun is a star).
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'sun'+'eg'='suneg'
'suneg' written backwards gives 'GENUS'.
'showing' acts as a link.
(Other definitions for genus that I've seen before include "Type" , "The Homo of Homo sapiens?" , "Biological group containing one or more species" , "Category between family and species" , "Group of plants with common characteristics" .)