Prickly shrub, one accommodated by Remus’s brother (5)
I believe the answer is:
brier
'prickly shrub' is the definition.
(I've seen this before)
'one accommodated by remus's brother' is the wordplay.
'one' becomes 'i' (Roman numeral).
'accommodated by' is an insertion indicator.
'remus's brother' becomes 'brer' (the Uncle Remus stories feature Br'er Rabbit etc).
'i' put inside 'brer' is 'BRIER'.
(Other definitions for brier that I've seen before include "plant" , "Thorny bush like the wild rose" , "It may be smoked" , "smoking pipe" , "Prickly shrub" .)