A broken chair, to many, is old (7)
I believe the answer is:
archaic
'old' is the definition.
(similar in meaning)
'a broken chair to many' is the wordplay.
'broken' indicates an anagram.
'to many' becomes 'c' (C is the Roman numeral for 100).
'chair' is an anagram of 'rchai'.
'a'+'rchai'+'c'='ARCHAIC'
'is' is the link.
(Other definitions for archaic that I've seen before include "Of a much earlier period" , "Extremely old" , "Antiquated" , "Antiquarian" , "Ancient or out of date" .)