Rum fellow, say, sporting red nails (8)
I believe the answer is:
islander
'rum fellow' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
'sporting red nails' is the wordplay.
'sporting' indicates an anagram.
'red'+'nails'='rednails'
'rednails' anagrammed gives 'ISLANDER'.
'say' is the link.
Can you help me to learn more?
(Other definitions for islander that I've seen before include "One living surrounded by water" , "person from Cuba?" , "man in Ibiza?" , "Sicilian, e.g." , "Inhabitant of a detached area" .)