Many an article is flexible (5)
I believe the answer is:
lithe
'flexible' is the definition.
(thesaurus)
'many an article' is the wordplay.
'many' becomes 'l'.
'an' becomes 'i' (Roman numeral for one).
'article' becomes 'the' (the 'definite article' part of speech).
'l'+'i'+'the'='LITHE'
'is' is the link.
(Other definitions for lithe that I've seen before include "Elastic" , "Slim and supple" , "light" , "Don -, opera by Verdi" , "quick to move" .)