Relative removes wall from stairwells (6)
I believe the answer is:
sister
'relative' is the definition.
(I know this)
'removes wall from stairwells' is the wordplay.
'removes' indicates anagramming the letters (I've seen 'removed' mean this (moved again)).
'from' suggests deleting specific letters.
'stairwells' with 'wall' taken away is 'stires'.
'stires' anagrammed gives 'SISTER'.
(Other definitions for sister that I've seen before include "Nurse, nun and sibling" , "Tender" , "twin?" , "Female relation" , "A relative to resist" .)