In a way that shows no understanding, interest or emotion. (Cambridge Dictionary)
In a way that is plain and characterised by a lack of decorative or other features. (Oxford Dictionaries)
In a way that shows a lack of interest or engagement. (Oxford Dictionaries)
In a way that temporarily shows no emotion or understanding, especially as a result of shock. (Oxford Dictionaries)
Young brunette woman blankly staring, on a green screen studio background.
Tony Abbott stares blankly at Julia Gillard for entire minute.