Maybe the second row’s not written about (7)
I believe the answer is:
ordinal
'maybe the second' is the definition.
I can't tell whether this definition defines the answer.
'row's not written about' is the wordplay.
'row' becomes 'din' (both can mean a loud disturbance).
'not written' becomes 'oral' (spoken rather than written).
'about' is an insertion indicator.
'din' inserted inside 'oral' is 'ORDINAL'.
Can you help me to learn more?
(Other definitions for ordinal that I've seen before include "Number defining a thing's position in series" , "Of position in series; service book (hist.)" , "Ranking number" , "Relating to position in a sequence" , "Denoting a numerical order in a series" .)