A girl from the east taking everyone aback (4)
I believe the answer is:
ella
'a girl' is the definition.
(girl's name)
'east taking everyone aback' is the wordplay.
'east' becomes 'e' (abbreviation).
'taking' is a charade indicator (letters next to each other).
'everyone' becomes 'all' (all people).
'aback' is a reversal indicator.
'all' in reverse letter order is 'lla'.
'e'+'lla'='ELLA'
'from the' is the link.
(Other definitions for ella that I've seen before include "Diminutive of Eleanor" , ".... Fitzgerald, late great jazz diva" , "- - Fitzgerald (mus.)" , "Great late jazz singer . . . . Fitzgerald" , "- Wheeler Wilcox, US poet" .)