Foe in eastern state holding me back (5)
I believe the answer is:
enemy
'foe' is the definition.
(I know that foe can be written as enemy)
'eastern state holding me back' is the wordplay.
'eastern' becomes 'e'.
'state' becomes 'ny' (short for New York).
'holding' indicates putting letters inside.
'back' says the letters should be written in reverse.
'me' backwards is 'em'.
'ny' enclosing 'em' is 'nemy'.
'e'+'nemy'='ENEMY'
'in' acts as a link.
(Other definitions for enemy that I've seen before include "Division" , "Yemen (anag.)" , "Hostile person, foe" , "Hostile opponent" , "Armed adversary" .)