Uncertain state that's ignored over border (4)
I believe the answer is:
limb
'border' is the definition.
(I know that limb is a type of border)
'uncertain state that's ignored over' is the wordplay.
'uncertain state' becomes 'limbo' (state of uncertainty).
'that's ignored' suggests deleting specific letters.
'over' becomes 'o' (cricket abbreviation).
'limbo' with 'o' taken out is 'LIMB'.
(Other definitions for limb that I've seen before include "Eg wing" , "as part of plane, say" , "Substantial branch from a tree trunk" , "Human's extension" , "Branch - member" .)