Battle-axes (x 2 defs) - 'aggressive women' & 'weapons'; wordplay is given by -
'Sarah' (battle, given as a synonym in Bradford's Crossword Solver [perhaps connected to the diminutive 'Sally'?]) + 'axes' (plural of 'axis', an alliance of powers)
Perhaps someone else can find a reference for 'Sarah = battle' - OED Online doesn't show it & I've not been able to find it elsewhere, sorry.