Add space symbol (5)
I believe the answer is:
totem
'symbol' is the definition.
(I've seen this before)
'add space' is the wordplay.
'add' becomes 'tot' (synonyms).
'space' becomes 'em' (in typography, a space as wide as a letter 'm').
'tot'+'em'='TOTEM'
(Other definitions for totem that I've seen before include "Image representing tribe" , "Emblem, maybe on pole" , "Venerated emblem" , "Sign" , "something sacred" .)