Iron Madame with big drink seen as a dangerous woman (5,6)
I believe the answer is:
femme fatale
'a dangerous woman' is the definition.
'iron madame with big drink' is the wordplay.
'iron' becomes 'fe' (Fe is the chemical symbol for iron).
'madame' becomes 'mme'.
'with' is a charade indicator (letters next to each other).
'big' becomes 'fat'.
'drink' becomes 'ale' (ale is a kind of drink**).
'fe'+'mme'+'fat'+'ale'='FEMME FATALE'
'seen as' is the link.
(Other definitions for femme fatale that I've seen before include "Alluring, seductive woman" , "Seductive woman who causes trouble" , "attractive woman" , "Vamp" , "Siren, bewitching woman" .)