A female with adequate business (6)
I believe the answer is:
affair
'business' is the definition.
(I've seen this in another clue)
'a female with adequate' is the wordplay.
'female' becomes 'f' (common abbreviation).
'with' means one lot of letters go next to another.
'adequate' becomes 'fair' (synonyms).
'a'+'f'+'fair'='AFFAIR'
(Other definitions for affair that I've seen before include "Romantic relationship between two unmarried people" , "scandal" , "Romantic relationship, perhaps illicit" , "Happening" , "Concern (maybe extra-marital?)" .)