Corrupt males entering one spoken exam (7)
I believe the answer is:
immoral
'corrupt' is the definition.
(similar in meaning)
'males entering one spoken exam' is the wordplay.
'males' becomes 'mm' (an abbreviation for male written twice).
'entering' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'spoken exam' becomes 'oral' (oral examination).
'i'+'oral'='ioral'
'mm' put into 'ioral' is 'IMMORAL'.
(Other definitions for immoral that I've seen before include "Ethically unprincipled" , "Dissolute or unprincipled" , "Without values" , "Licentious - dissolute" , "Unprincipled or debauched" .)