European married iron lady in power (7)
I believe the answer is:
empress
'lady in power' is the definition.
'european married iron' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'married' becomes 'm'.
'iron' becomes 'press' (I've seen this in another clue).
'e'+'m'+'press'='EMPRESS'
(Other definitions for empress that I've seen before include "Delilah?" , "leading lady" , "She rules over many territories" , "She rules over vast territories" , "Powerful woman" .)