Common sense to embrace new words for things (5)
I believe the answer is:
nouns
'words for things' is the definition.
(I've seen this before)
'common sense to embrace new' is the wordplay.
'common sense' becomes 'nous' (nous is a kind of common sense).
'to embrace' means one lot of letters goes inside another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'nous' enclosing 'n' is 'NOUNS'.
(Other definitions for nouns that I've seen before include "Words referring to people, places or things" , "They refer to people, places and things" , "Identifying words" , "terms" , "Words referring to person, place or thing" .)