Name Australopithecus, for example, one not quite a success (6,3)
I believe the answer is:
nearly man
'one not quite a success' is the definition.
(I've seen this before)
'name australopithecus for example' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'australopithecus for example' becomes 'early man' (early humanoid species).
'n'+'earlyman'='NEARLY MAN'
(Other definitions for nearly man that I've seen before include "not a complete success" , "one failing to fulfil his potential" , "one who didn't quite make it" , "not the expected success" , "not quite a success" .)