Small German greeting a female informally (6)
I believe the answer is:
sheila
'female informally' is the definition.
(informal Australian term for a woman)
'small german greeting a' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'german greeting' becomes 'heil' (a greeting in German, like 'hail').
's'+'heil'+'a'='SHEILA'
(Other definitions for sheila that I've seen before include "Victorian woman, perhaps" , "Aussie lady?" , "bird?" , "Girl's name (any Oz girl?)" , "Female name" .)