An article to smile about, just a little (5)
I believe the answer is:
grain
'a little' is the definition.
(thesaurus)
'an article to smile about' is the wordplay.
'an article' becomes 'a' (English indefinite article).
'to smile' becomes 'grin' (grinning is a kind of smiling).
'about' is an insertion indicator.
'a' put inside 'grin' is 'GRAIN'.
'just' is the link.
(Other definitions for grain that I've seen before include "Cereal crops" , "cereal crop" , "Enter into combat with" , "Particle of e.g. sand" , "bit of corn" .)