Odd couple in some article: a sleep-inducer? (7)
I believe the answer is:
sandman
'a sleep-inducer?' is the definition.
(imaginary spirit which makes people sleep)
'odd couple in some article' is the wordplay.
'odd couple in' becomes 'sandm' (I can't justify this - if you can you should believe this answer much more).
'some article' becomes 'an' (indefinite article).
'sandm'+'an'='SANDMAN'
(Other definitions for sandman that I've seen before include "One of the Beach Boys" , "Imaginary person who causes children to sleep" , "Fictional character" , "He comes to send children off" , "Sender to sleep of children" .)