French on about Welshwoman showing tongue (7)
I believe the answer is:
russian
'tongue' is the definition.
(Russian is an example)
'french on about welshwoman' is the wordplay.
'french on' becomes 'sur' ('on' in French).
'about' shows that the letters should be reversed in order.
'welshwoman' becomes 'sian' (common Welsh name).
'sur' reversed gives 'rus'.
'rus'+'sian'='RUSSIAN'
'showing' is the link.
(Other definitions for russian that I've seen before include "Countryman" , "Muscovite, maybe" , "Slavic language" , "East European" , "Native of St Petersbourg, say" .)