Woman hiding information makes plan (6)
I believe the answer is:
agenda
'plan' is the definition.
(agenda is a kind of plan)
'woman hiding information' is the wordplay.
'woman' becomes 'Ada' (woman's name).
'hiding' indicates putting letters inside.
'information' becomes 'gen' (gen can informally mean information).
'ada' going around 'gen' is 'AGENDA'.
'makes' acts as a link.
(Other definitions for agenda that I've seen before include "List of items to be dealt with" , "List of items of business for committee" , "List of matters to be discussed at a meeting" , "List of business for a committee meeting" , "matters for discussion" .)