For example, first racket during exam (7)
I believe the answer is:
ordinal
'for example first' is the definition.
('first' is an example)
'racket during exam' is the wordplay.
'racket' becomes 'din' (I've seen this before).
'during' indicates putting letters inside.
'exam' becomes 'oral' (oral exam is a kind of exam).
'din' placed into 'oral' is 'ORDINAL'.
(Other definitions for ordinal that I've seen before include "Numerals such as first and second" , "It shows your place" , "Old Iran (anag)" , "First, second, third could be such a numeral" , "Like "first" or "third"" .)