Sky feature about Irish sport succeeded (6)
I believe the answer is:
cirrus
'sky feature' is the definition.
(type of cloud)
'about irish sport succeeded' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'irish' becomes 'IR' (abbreviation).
'sport' becomes 'RU' (rugby union).
'succeeded' becomes 's' (genealogical abbreviation).
'c'+'ir'+'ru'+'s'='CIRRUS'
(Other definitions for cirrus that I've seen before include "Thin, wispy cloud" , "High, thin cloud" , "Wipsy white cloud" , "Wispy white cloud" , "Type of cloud" .)