Excite woman with union (5)
I believe the answer is:
rouse
'excite' is the definition.
(I know that excite can be written as rouse)
'woman with union' is the wordplay.
'woman' becomes 'rose' ().
'with' indicates putting letters inside.
'union' becomes 'U' (common abbreviation as in 'Trades Union Congress').
'rose' going around 'u' is 'ROUSE'.
(Other definitions for rouse that I've seen before include "Wake up, make active" , "Stir up; excite" , "Inspire" , "To start" , "Prod" .)