Mary delirious about new introduction to Adonis (7)
I believe the answer is:
madonna
'mary' is the definition.
(Madonna refers to the Virgin Mary)
'delirious about new introduction to adonis' is the wordplay.
'delirious' becomes 'mad' (synonyms).
'about' becomes 'on' (as in a book 'on' a certain topic).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'introduction to' suggests taking the first letters.
The initial letter of 'adonis' is 'a'.
'mad'+'on'+'n'+'a'='MADONNA'
(Other definitions for madonna that I've seen before include "Religious work" , "Virgin Mary - or American showbiz queen" , "American pop singer" , "Representation of the Virgin Mary" , "religious painting" .)