Irish as football! (6)

I believe the answer is:
gaelic
This could be a double definition.
'irish' is the first definition.
(I've seen this in another clue)
'football' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'as' is the link.
Can you help me to learn more?
(Other definitions for gaelic that I've seen before include "Language of the Celts" , "Irish language or Celtic language of Scotland" , "The native language of Ireland" , "tongue" , "Speech" .)
