Perhaps pens article about English or Welsh football club (7)
I believe the answer is:
swansea
'football club' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'perhaps pens article about english or welsh' is the wordplay.
I cannot quite understand how this works, but
'article' could be 'an' (indefinite article) and 'an' is present in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is found within the answer.
'english' could be 'e' (abbreviation) and 'e' is found in the answer.
'welsh' could be 'w' and 'w' is found in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for swansea that I've seen before include "Birthplace of Dylan Thomas" , "Home of the DVLA" , "South Wales port" , "Welsh city" , "Ecstasy, a win! (anag)" .)