Take over, thus making a woman cross (5)
I believe the answer is:
annex
'take over' is the definition.
(I know that annex is a more specific form of the action take over)
'a woman cross' is the wordplay.
'a woman' becomes 'anne' (woman's name).
'cross' becomes 'x' (X is cross-shaped).
'anne'+'x'='ANNEX'
'thus making' is the link.
(Other definitions for annex that I've seen before include "Attach(ment)" , "Add to one's territory" , "Add to the end; take possession of" , "Extension to a main building" , "Add by conquest or occupation" .)