Article about ultimately fair English Cardinal (5)
I believe the answer is:
three
'cardinal' is the definition.
(similar in meaning)
'article about ultimately fair english' is the wordplay.
'article' becomes 'the' (the definite article in English).
'about' means one lot of letters goes inside another.
'ultimately' suggests the final letters.
'english' becomes 'E' (abbreviation).
The final letter of 'fair' is 'r'.
'r'+'e'='re'
'the' placed around 're' is 'THREE'.
(Other definitions for three that I've seen before include "Number of times N appears in this completed grid" , "So many 12s today" , "A crowd, you might say" , "Subject of 1 9" , "Number of feet in a yard" .)