fainne
A pin badge worn to indicate a fluency in, or a willingness to speak, the Irish language.
In the past, the 'Fainne' got something of a bad name because not all of its wearers were prepared to confine their attempts to converse in Gaelic to fellow-members of the League; some insisted on trying to do all their shopping in Irish...
1966 The Irish answer: an anatomy of modern Ireland. Tony Gray
Where it comes from
Borrowed from Irish fáinne (“ring”). Doublet of fawny.
Adapted from the Wiktionary entry fainne (CC BY-SA 4.0).